All right. Welcome, everyone, to today's Webmaster Central Office Hours Hangout. My name is John Mueller. I am a Webmaster Trends Analyst here at Google in Switzerland. And part of what we do are these Office Hour Hangouts, where people can join in and ask any question around their website and web search. A bunch of stuff was submitted on YouTube, again, which is great, a good way to get these questions in. But as always, if any of you want to get started with the first question, you're welcome to jump in now. Hey, John, can I go first? Sure, go for it. All right, so my question is regarding a query site colon domain name dot com. So usually, when we want to see if the specific page is indexed in Google other than Search Console is when I do a site colon query directly on the web. I see the home page is not coming up, which was coming up back in the time. And any time I go back in the Search Console and resubmit it, I see it coming up for 24 hours, like for a day, and then it disappears. Surprisingly, that page is still coming up normally or working fine for one of the competitive keywords. It's not like it's one of the blacklisted page. If it was an internal page, I would not worry because of a variety of reasons. But since this is the home page, I don't know, should I be worried? And there are no signals in Search Console that is showing me an error. AMP version and all looks fine. Yeah, that's something that comes up every now and then. But it's not a sign of anything being wrong or anything broken. The main reason you're seeing this is that for site queries in particular, we don't have any defined order that we would show them. So it's very common that you would see the home page first or on the first page of a site query, site colon results. But it's not always the case. And it's not a sign that there's anything wrong with the website or anything kind of blocked or, I don't know, otherwise problematic. So if it's ranking normally, I think you're OK. Even though it doesn't appear at all in all the pages, I mean, at all is kind of tricky because of the way that things get filtered out from a site colon query, where we try to filter out things that are kind of duplicate, where we already have shown the same title and description. And because of things like that, the site colon query isn't really meant as a comprehensive list of all the pages that we have indexed. And since it's an artificial query, we don't have any kind of defined order for the site colon results. So nothing to worry at all. It's just completely natural to have the home page missing in it. Yeah. I mean, on the one hand, for site colon query, that's something that happens every now and then. It sometimes also happens that even within a website, some other page is seen as a primary page for the website. So even just from the point of view, what is your primary page? Sometimes that's not necessarily the home page because I don't know, a variety of reasons. Maybe some product that you have is what your whole company is known for. And that's some subpart of your website. Got it. OK. Thanks. Cool. I had a question. A lot of people who are doing personalization now are talking about adaptive content for their, like for example, their mobile home page versus their desktop home page. And with mobile indexing, how does Google feel about adaptive content where the content on the mobile version doesn't necessarily contain all of the same content that's on the desktop? Ultimately, that's something that you kind of have to decide for yourself. Because from an indexing point of view, we will index the mobile version of the home page. And usually, we crawl an index from US-based IP addresses. So if you're doing adaptive content by country or by language or by city or something like that, then that would also play into that. But essentially, we would index the content that we would see. And if you show users other content for other locations or other devices, that's kind of up to you. The only problematic case where someone on our side might get involved is when it gets into more malicious content. Where maybe you show, I don't know, comic books on the mobile version, which is the one that we index, and the desktop version is an adult website or something crazy. That's something that we don't see very often. But it can happen every now and then. But if you're adjusting the content slightly differently, if you're saying, well, on mobile, people don't want to read as much. So we have a shorter version of the page. And on desktop, we have maybe more links to PDFs or something like that. That's completely fine. Totally up to you. The only thing to keep in mind is that we'll just index the mobile version. So we won't look at the desktop version at all. If there's something that you want your site to be known for that's only on the desktop version, we might not know about it. Makes sense. Thank you. Cool. Thanks. I do have a follow-up note on that. What we have been doing is we'll try and replicate the same content considering for ranking. But for a mobile version, we'll probably add a link called Read More. So if someone wants to sit down while they're driving or anything on an iPad or something, they can. Otherwise, they see a very smaller version of the same piece of content. Since that is what Google is going to consider for ranking, I don't know if that makes sense, like if it's OK or not. I mean, from our point of view, that's OK. I don't know if users always appreciate that, because lots of people on mobile do want to see the full content. But that's ultimately up to you. So we'll just index the version that you have on the mobile version. And if that's all you want to have index, that's up to you. If you prefer to have more index, then make sure that more content is on the mobile version as well. Got it. OK. Let me jump into some of the submitted questions. And if you all have any questions along the way, feel free to jump in. Or if there's anything kind of related that comes up, feel free to bring that up. Let's see. I think this is a similar question already. A question around cloaking in general. In some situations, we display slightly different content for US IPs, for our domains, with non-English language to optimize the way that Google indexes our site. As Googlebot is majorly coming from the US, do we risk any cloaking penalty with this behavior? How does Google define or detect cloaking in general is the same IP, the same content, safe enough of a solution? So in general, the thing you would need to watch out for is that you're not serving Google or search engines, specifically different content. If you're serving all users in the US this content, that's perfectly fine. That's the version that will index. If users from other countries see slightly different content, that's ultimately up to you. In an ideal world, we would be able to crawl and index from all of these different countries and see all of those versions of the content. But for practical reasons, just crawling the web once is already pretty hard. So that's not something that we can easily expand to all other countries. So if you're showing content to users in the US and Google is crawling from the US, then that's what we would index. That's not something that we would consider cloaking. When it comes to cloaking, if the web spam team suspects there is cloaking happening, then they have lots of sophisticated means to test that. So that's kind of something where I suspect it's not anything you need to worry about if you're doing this in a reasonable way. But the web spam team does sometimes take time to figure out what's actually happening here and to make sure that it's not causing any problems in our search results. And then a question regarding 301 redirects. For strategic reasons, we would like to redirect all users coming from IP addresses, from a certain country, to a different domain. Let's say we have domain or abc.info, and we redirect every user coming from a Russian IP to xyz.org. xyz.org would have canonical pointing to abc.info. The reason is we want abc.info to rank and xyz.org to serve visitors from Russia. Do you see any risks here which might harm the rankings of abc.info? In general, this is something that you can do. I think you probably want to watch out that your users are also happy with this, because ultimately, if your users learn that your website is not what they were looking for, then they'll go elsewhere anyway. But in general, when it comes to internationalization, you can have a setup where you have something like a central home page that redirects users from different countries to different versions of your site. The thing to watch out for, again, is we will crawl an index from the US. So if you always redirect US users away from your Russian content, we would never recognize that you actually have Russian content, which might make it hard for you to rank for all of these Russian keywords, for example. But in general, this kind of a setup is something you can do. You can use hreflang to tell us about this and kind of flag the redirecting page as an X default page. And by that, we will generally learn which versions to show in search. It's not always guaranteed that we will show the kind of canonical URL or the one that you have the rel canonical to. So if we see lots of signals telling us, actually, your Russian site is the one that people prefer, then we might index that URL as your main website. So for canonicalization, we use the number of different signals. The redirects help us. The rel canonical helps us. But we also look at things like links internally and externally, sitemap files, all of the other signals that we have there. So that's something just to keep in mind if you're seeing that the wrong version is being indexed. What's a typical timeline for large corporate site to see sitelink search box to be removed from search results? I assume this is if you add the no sitelinks. I don't know what the exact meta tag is called. But there's a meta tag that you can add that removes the sitelink search box. If you add that to your pages, then generally, over time, we will drop the sitelink search box for that site. I don't know how long that takes to be processed. I do know that if you add the markup to provide your own sitelink search box with your own website, that can sometimes take quite a bit of time. So with some kinds of structured data, we can pick that up within a couple of days. With the sitelinks markup, I've seen it sometimes take a month, maybe a little bit longer. So sometimes that just takes longer to be processed. We changed one of our sites, title and description and content, three weeks ago. NFL schedule to the new season. And at first, Google displayed the new snippet and ranked the site quite well. However, after three days, Google displayed the old snippet and ranked us on page two. Since then, the snippet and the ranking are switching about every three days. Googlebot crawled the site several times. Since then, what's the matter here? I don't know. It's really hard to say without an example. This sounds like something that shouldn't be happening like this. So if you want to send me some examples of where you're seeing this happening, Florian, then feel free to do that. Feel free to ping me on Twitter if you want or add some more details to the question here. What's Google's policy on back button hijacking? Sites like Gear Hungry, once you visit from Google and click the back button, they take you to the home page instead of Google search results. Is there a penalty for such action? Or is it loud? It feels kind of sneaky. So this is something which I certainly wouldn't recommend doing because if people want to go somewhere, then it's probably a good idea to let them go there. I don't think they'd be happier if you just sent them to your home page. I'm not aware of any specific policies on our side with regards to back button hijacking. So I don't know if that's something that the various Google teams would really worry about there because it's really something more where you're annoying your users. It's not that you're causing problems in search. Question about EAT and YMYL. So EAT is expertise, authority, trustworthiness, and YMYL is your money or your life content. These are terms from the Google Raider guidelines that we put out. We're working with news websites. What tips can you give us about indication of content authors? Is it really necessary to make pages for each author, provide big info with photo, bio, links to social networks? I mean, that this really matters, that there are lots of work to do elsewhere. I think with all kinds of content, it's not the case that you can say this really matters and you absolutely must do it. I do think with a lot of news websites, especially if you're providing information that you want people to trust, then this certainly makes sense. So it's not something where I'd say it's the same as removing a no index meta tag on a page because that's really on and off switch. But if you're improving the content of your site, that works well for users. That works well for Google. So that seems like something that could be done. How to prioritize that versus other things on the website, that's really hard to do. That's where you almost need to use your experience and figure out what works well on your side. Let's see. We're publishing news articles, or news and articles. For example, we have 100 new articles every day. 10 of them give us 95% of the organic search traffic, another 90 go nowhere. We're afraid that Google can decide our website is interesting only for 10%. There's an idea to hide some boring local news under no index tag to make the overall quality of all publishing content better. What do you think? In general, we do look at the content on a per page basis, and we also try to understand the site on an overall basis to understand how well is this site working? Is this something that users appreciate if everything is essentially working the way that it should be working? So it's not completely out of the question to think about all of your content and think about what you really want to have indexed. But especially with a news website, it seems pretty normal that you'd have a lot of articles that are interesting for a short period of time that are perhaps more of a snapshot from a day-to-day basis for local area. And it's kind of normal that they don't become big popular stories on your website. So from that point of view, I wouldn't necessarily call those articles low quality articles, for example. On the other hand, if you're publishing articles from hundreds of different authors and they're from varying quality and some of them are really bad, they're kind of hard to read, they're structured in a bad way, the English is broken. And some of them are really high quality pieces of art almost that you're providing. Then creating that kind of a mix on a website makes it really hard for Google and for users to understand that actually you do have a lot of gems on your website that are really fantastic. So that's the situation where I would go in and say, we need to provide some kind of quality filtering or some kind of quality bar ahead of time so that users and Google can recognize this is really what I want to be known for. And these are all things, maybe user submitted content that is something we're publishing because we're working with these people, but it's not what we want to be known for. Then that's the situation where you might say, maybe I'll put no index on these or maybe I'll initially put no index on these until I see that actually they're doing really well. So for that, I could see it making sense that you provide some kind of quality filtering, but if it's a news website where kind of by definition, you have a variety of different articles, they're all well written, they're reasonable, just the topics aren't that interesting for the long run, that's kind of normal. That's not something where I'd say you need to block that from being indexed because it's not low quality content, it's just less popular content. In my search console account, I see a lot of URLs in the coverage report that returns status code 500. However, there are URLs that existed by the buttons for sharing the page on social networks under the path social network slash Facebook slash ID, for example, but those URLs are not returning a server error but a temporary 302 redirect towards a social network. How can I correct these errors when they're really not from our site? Okay, so that sounds like these errors are things that happen when you redirect to an external site and there are things where essentially on your site, everything is working well and the external site is maybe serving a 500 error or serving something else where for whatever reason it's not returning a normal 200 result. That's something that essentially doesn't bother us that much. We will flag it in search console because it is something where we tried to crawl a URL on your site and we ended up on an error page, which could be kind of a sign that there's something weird happening, but if you're aware of this, then that's generally not a problem. What you could do is perhaps block these by robots text, these URLs on your site because those are not things that really need to be crawled and indexed. So from that point of view, you can prevent that error from appearing in the crawl errors by blocking them by robots text. In general, I don't think that would cause any problems overall, so that's probably the direction that I would go there. What might happen is that if you do a site query for these specific directories on your site, then maybe we would show these URLs without a title, without a description because they're blocked by robots text, but if you do normal queries for your website and these aren't things that would be showing up in the normal search results, so that's not something you'd really need to worry about. Does Google ever use historic data when deciding how to rank a site or do the algorithms only look at the present and most recent snapshots? I mean, can a website build up goodwill over a period of time, which may help it? Yes, in some ways that that can happen. So in particular, if you have a website that has existed for a very long period of time, then that's something where the whole ecosystem around the website will have evolved around that. And there'll be links from all over the web for a longer period of time. And when we look at that website, we will see kind of the current snapshot of the website, what we recently crawled, but all of these signals that have been collected over the years. So that's something that can definitely play a role. There are also signals within search, specific to a website that might be collected over time. The ones that I've run into a few times are generally around adult content. So that's something where if a website for a longer period of time provided adult content, then our algorithms might start learning that actually we need to filter this using Safe Search. And if that website were to completely revamp the whole website and it was suddenly, I don't know, a non-adult website, then it can happen that for a period of time those Safe Search algorithms will try to stay on the safer side and might still filter that site in Safe Search for a while. So that's something that can sometimes take a bit of time to settle down. Similarly, with some of the quality algorithms, it can also take a bit of time to kind of adjust from one state to another state. So if you significantly improve your website, then it's not that from one crawl to the next crawl, we'll say, oh, this is a fantastic website now. It's something where probably over the course of a year, maybe sometimes even longer, our algorithms have to learn that actually this is a much better website than we thought initially. And we can treat that a little bit better in the search results over time. So that's something where essentially the historic data that you mentioned there is not historic in the sense that it's like 10 years old data, but it's more that sometimes the status of things maybe a year or even two years ago can still play into how a website is ranked in search now. Regarding one point I came across recently, does the link pass page rank on a page that I have temporarily removed in Search Console? Yes. So temporary removal in Search Console does not change anything about indexing of a page. It really just hides that page in the search results. So that's something where essentially from our side, we want to provide a way to make it possible for people to remove things as quickly as possible. And if we needed to go through the whole indexing system to do that, that would take quite a bit of time. So the temporary removal essentially just hides it in the search results. It doesn't change anything from the indexing side. For the indexing side, we still need to recrawl and re-index that page. If that page is now gone, if it has a no index meta tag on it, then we'll be able to take that into account. The next time we kind of have reprocessed that page and when the temporary removal expires, for example. So similarly, if you add a link to a page and this page is something that is temporarily removed in Search Console, then when we recrawl that page, we will find that link. We will treat that as a normal link, as would any other link in indexing. And we might crawl the page that is linked or we might pass some signals to the page that is linked from there. Can I use a 301 domain after a year or so? And what amount of page rank will transfer? Not quite sure how you mean that. But in general, if you're moving from one domain to another, then 301 redirect is the right way to deal with that. And with a clean 301 redirect, if you're redirecting every page one by one and there's nothing left on the old website, then we will try to pass all of the signals as much as possible. And the signals include page rank. We use a lot of other signals, though. So it's not really not just page rank that is being processed there. If you wait with this redirect, if you do a partial redirect from the website, if you do a redirect in a way that makes it hard for us to recognize that this is a one-to-one site move, then that makes it a lot harder for us to process those signals and to forward them on. That means essentially what usually happens is it takes a lot longer and the outcome is not so clearly defined. So if you're redirecting a part of a website, then we essentially have to reprocess both of those, the old and the new website, and try to figure out what the new status of this website should be. So it's not that we would just pass everything on. We kind of have to recalculate everything. Similarly, I think maybe this question goes in a direction. I was like, what if you only start setting up the redirect a year after you actually do the site move? For the most part, we will try to recognize site moves, even without a clear redirect, but it's a lot harder. And if you wait a year to set up this redirect, then it's kind of a long time already, and things have already settled down a little bit. And what the final state there will be is really hard to predict. So I think adding a redirect later, if you forgot that with a site move, is always a good idea. If you wait very long, like a year, then I don't know what effect you would effectively get from that. I'm trying to move my landing page from WordPress to a new React framework server on server side render page. The new React page gets an almost perfect score in every category in the DevTools audit. It scores far better than the WordPress page. I've copied almost all the content word for word from the WordPress site over to the new React site. I ended up changing my name servers from AWS GoDaddy to Zyte and ended up losing my rankings. I'd love to know how to migrate a site properly. And not sure what the main problem is with moving things over is the name server or DNS records is a difference WordPress adds a lot of metadata and has a lot of plugins. Yeah, I don't know. So from just from a purely technical point of view, like taking aside moving from WordPress to a React framework, it sounds like you're essentially restructuring your website. You're revamping the whole website. And that's probably the part where our systems got confused or where our systems are running into issues. So it's less a matter of what technical infrastructure you're moving across, but more that you essentially have a new website. So the changing of the name servers, I would see that as totally inconsequential. That's something unless the new name servers are completely unreachable by Google, then that's totally irrelevant. But what probably plays a role here is the change of the site itself. So copying the content word for word is one thing, but there's a lot more on a website rather than just the words on a page. There are things like titles and headings on a page.  There is the design of the page itself, the internal linking, the navigation. All of that plays into us understanding what this website is about and how the individual pages are connected to each other. So that's something where sometimes if you take the content and just copy it word for word to something else, then we can still understand this is the same content. But we might have trouble understanding the emphasis of the individual pieces of content. Things, like I mentioned, like the headings or the elements that are somehow otherwise kind of emphasized within the pages. So that's something where I could imagine you might be running into problems there. The other thing is depending on what all you changed, if you changed the URLs themselves, then you'd also need to set up redirects between the old URLs and the new ones. Sometimes if you're migrating from one CMS to another CMS, these URLs change. Sometimes you can keep them the same. If you can keep them the same, that's an optimal situation. If they change, then we essentially have to reprocess the whole website again. The internal linking is the other part that I briefly mentioned, things like the navigation, how you link the various pages and parts of your website together with categories and kind of higher level pages and maybe snippets and overviews, all of those things. That also plays a role in with how we can index your pages properly. So that's something where I'd also watch out for that. The other thing that might be playing a role is with regards to moving from kind of a static HTML version to a more JavaScript-based version. It sounds like you're doing server-side rendering, which would mean that the new website is also a static HTML page when we try to crawl and index it, which means it's more like the same situation. But at the same time, if you're doing this kind of server-side rendering for Google specifically, then there are lots of opportunities for things to go wrong that you might not be seeing as a user. So especially if you're doing something fancy for Google in that regard, then it's something where you just have to check a lot more things. So my recommendation here would be to try to figure out the differences as quickly as possible. So if you still have a backup of the WordPress site, then maybe install that on a different server somewhere so that you can crawl the whole website. You can compare it on a page-by-page basis with the new website so that maybe using some third-party crawling tool, figure out, is the internal linking the same? Are the same URLs being used before and afterwards? If not, is that something that you can still tweak on your new website to make it more the same? How do the individual pages look? Do they have headings, titles? All of these things do they match? That's something that also plays a little bit of a role there. Let's see, the metadata that you mentioned, a lot of the metadata on pages are things that we can ignore. Sometimes they're relevant for social media sites, like finding what is a thumbnail image that should be shown for this page. Those are things, probably worth adding anyway. But that's not something that we would use for indexing and ranking. There are some other types of metadata on pages, though, that we would use, especially if it's something that we would pick up for structured data or if it's something that we would show maybe as a description in the search results page. Both the description and structured data are not things that we would use for ranking, though. But you might see that in that your search results entry looks a little bit different. And if it looks a little bit different, maybe users respond to it a little bit differently. Yeah, wow, so many things to watch out for. But my general recommendation with this kind of situation is to try to understand exactly what's happening as quickly as possible. Because the longer you let it sit in this state of being different and you're not sure exactly why it's behaving differently, the more likely our systems will just learn your new website and say, well, it's a different website. We should rank it differently, but we've learned how to deal with it. Whereas if you can fix these things as quickly as possible, then we can understand a little bit better. Oh, wait, this just tweaked slightly. We can take all of the existing signals that we have and apply them to the new website. Kind of weird. I thought I had a lighter question. Go for it. Sorry, go ahead, I'm on the first. Sure, a bit of a lighter question, one that hopefully has a relatively quick answer. Are there plans in Search Console to bring back the highlighter tool? I'm thinking for people that either don't have access to developers or who are on large enterprise sites where developers are tied up on things. Yeah, so it's still there. It's just kind of hidden away with the old tools at the moment. But it is something that the team is looking into, how we can migrate that to the new infrastructure.  And it's sometimes really useful to be able to prove to people that actually it's worthwhile doing. So that's something where I think there's some options there. Another thing that we noticed is with Google Tag Manager, you can sometimes also do similar things in that you can add structured data and let that be picked up like that. It's a little bit more complicated, but it might also be an option. The question I had around the site move is one of like any other SEO guys out there have burnt hands using changing the website, right? I don't think I have yet to see a migration that goes smooth. If you're ranked on top 10, you're getting decent attraction. You want to make it mobile friendly. You always want to do the next step. So is there any plan from Google to provide some kind of assistance in the search console or somehow saying tag, hey, we are migrating a new site. So don't burn the signals. We'll keep the same URLs. Obviously, when you move from one CMS to the other, you set an example of CMS or a different server slash new code, you are going to expect a complete design change. The user can make sure the UI can remain the same or the link slash content. But there is so much that runs behind it. And if Google is going to reprocess it, it's like a new marriage after everything's like start all over again. So I mean, is Google trying to not promote users to come out with new websites and let's give a better experience or what's the, how can you help us better like the whole community? Yeah, good question. I think the general situation with a lot of these site revamps is also that you're trying to improve things. So that's something where I think sometimes it does make sense to rethink the signals because these signals can also improve in a positive way. It's definitely not the case that every site migration that you do will always result in negative signals and kind of things getting lost because a lot of times you will be able to work on a website and you recognize all of these problems and then you create a new structure, a new website. And it doesn't have any of these problems. And you want that work that you worked on to be reflected well in search as well. So that's something where I don't know. It's kind of tricky to say that we should keep the signals and not let a site be able to profit from the improvements there. But it is always tricky because I think the part that always makes it hard for me when talking about this is that it's hard to judge ahead of time what the actual effects will be. And especially if you don't have a lot of experience around SEO, then it's really hard to judge what will actually happen when we switch over. And the other thing that I always see as well is that sometimes these kind of site revamps are done by people who don't actually know much about SEO, who are maybe the developers or maybe the design team or marketing team that says, oh, we need a new website. We will outsource a new website. It looks really nice. It's really fancy. And they don't realize that all of these changes could potentially affect the search visibility as well. Things like removing text and putting it into images. It looks the same in a browser, but it reacts very differently. And as an SEO, when you look at this new site, you say, well, this is a problem. This is something that we need to fix. Um, yeah, it looks. It's weird with someone mentioned that people are having trouble getting in. I don't know. That is kind of weird. Usually I get a little pop-up saying that people want to get let in. But that doesn't seem to be happening at the moment. I don't know. It's hard for me to figure out what exactly is stuck, but. But so there are no plans from Google to kind of help with this problem, right? Like from the webmaster team, I guess. So I think the one thing that we've been looking at is specifically for site moves to have at least some kind of progress indicator that lets you know that when Google has finished reprocessing your kind of site migration, your site move setup, that I think makes it a little bit easier to understand when you've reached the kind of final state where it's not that you're in this uncertainty of, do we just need to wait for Google to figure it out? Or is there actually something that you need to do differently to move into a different situation? Yeah, I think that would be very helpful because when to panic, wait, Google is still working on it. Give it six months. That's fine. The wait is fine as long as we know it's in transition or it's progressing. And going back to the other thing that we talked that you discussed earlier from one of the other users about content. So I had a site, the content wasn't changed in five years, seven years. Certainly the guy is free because of this pandemic. He's like, let me revamp the content. I haven't changed in a while. And he didn't see any positive result. And I kept telling him content is the key. He's like, it didn't change anything. I'm like, I guess we need to wait. And I don't know if there is a temporary removal, just like a new, hey, I can indicate somewhere in the search console, this is a new page. And if Google wants to take six months to settle down, it's fine. It would be nice to see the progress, like you said, site move versus if you tag a new page. I don't know if that's even possible, but yeah. Yeah, I think it's always a bit tricky because there are always some things that change on a website. And it's hard to understand when you just need to let the systems figure it out on a website if there's something that you need to change yourself. Now, I don't know. Good point. I think that's something we can certainly think about and see if there is something that we can do there. One of the things that we did add in Search Console with the new version of Search Console is the general concept of being able to validate fixes. Maybe that's something that we could implement there in general, where you can say, well, I've revamped my content. I would like Search Console to kind of validate the changes that I've made with the validation process in Search Console. At the moment, it's tied to issues that we recognize, which are usually technical issues, like structured data or indexing. And what will happen there is we will try to re-crawl and re-process the website a little bit faster so that we can reflect that new state in the index a little bit quicker. So maybe that's something that we could also expand to more kind of content or revamped situations as well. Yeah, that's exactly what. So unless the user checks in manually, so you are waiting for an input from the company or someone to say, hey, this is new. And then you say, all right, I'm going to do it again. And I'm also going to show the progress this time or something. Yeah. Thanks. Regarding the people that can't seem to get in, I don't know why that seems stuck. But I suspect maybe it's tied to the recording that's running. So once we pause the recording, we'll see if that starts working again. I don't see any other option of adding people unless I have their email addresses, which I don't really have any. Sorry, I posted that. I can get them to try. They tried a few times. Do you want me to get them to try now? Yeah, OK, well, maybe we'll just pause the recording and keep it shorter and see if more people can join in. All right, thanks for watching. And if you found this useful, feel free to hang around on the channel. And maybe we'll see each other again a little bit later. All right.


I recommend that everyone does an apprenticeship. It was a great opportunity that I didn't really think about when I was in high school. The apprenticeship program at IBM was really the vector to achieving my dreams. What I love about the program is that I can apply what I learned in class in my job every day. I was able to learn the technical skills about user experience and gain a certificate for it as well as professionally develop myself. I was on the job learning, actually participating in classes that mattered in my field. Thanks to that I'm a homeowner at the age of 25. To me apprenticeship means seizing your learning and seizing your life.


So back in the day to sell your house you would put an ad in the newspaper. Every Sunday would come out everybody would get the ad you'd see the houses for sale. There are also little magazine booklets that you could buy or pick up at the grocery store. Used to sell your house almost every time. You could do an open house and get a lot of people through but that is no longer the case. You can still do open houses and get a lot of people through but it's going to be through a different avenue. Digital marketing is the way to sell your house. If you are working with an agent and they do not come to you with a good solid digital marketing plan then you're really going to struggle in this day and age. People are buying homes online via Zillow, Trulia, Realtor, all those different websites and they're flicking through and if they're not attracted to the home by the first couple pictures then you just get skipped over. You're just noise. The only way that you're going to really be able to make a big splash in the market is by having a good plan in place. If you have any questions please reach out to me. I'd love to give you some tips and ideas of how to market your property online. Thanks and have a great day.


Hi, I'm Zor. Welcome to New Zor education. Today, I would like to talk about some physical sense of anti-derivatives and integrals. Basically, this mathematical apparatus like differentiation and integration, they did not really appear in just vacuum. Somebody came up with these procedures. Well, the beginning of the process of developing these mathematical apparatus were people who were very much concerned about physical sense of whatever we're all doing. And primarily Sir Isaac Newton and Leibniz, they were in the beginning of mechanics, as we know it right now, classical mechanics. And all these procedures, differentiation and integration, were basically invented by them and some other people who developed it for the purpose of better explaining what's going on in the nature. So, being as it may, I would like to switch from the previous lecture where I was explaining basically purely mathematical apparatus of integration to something which is a little bit more physical, primarily to justify whatever mathematical apparatus we are using, whatever mathematical principles are in these purely physical concepts of mechanics, for instance. Now, you do remember that when I was trying to explain the principles of differentiation, I was talking about speed or rate of change as basically the physical principle on which differentiation actually is based. So, let me just go back and, well, not repeat, but remind you what exactly that was all about. Let's consider the R moving along certain trajectory. And our movement is basically controlled by certain mathematical function which tells us how much distance we have covered from the moment t equals to zero to current moment t. So, let's say we started here. So, for every moment t, this is t equals to zero. So, for every moment t, we know how much distance we have covered during our trip. So, and that's what actually s of t is the length of this piece. So, this is moment t. Now, what we did next, we were talking about the speed. And first, we decided that if you have certain interval of time from t to t plus delta t, then during this time, we have covered the distance from s of t to s of t plus delta t. So, we have covered the difference in distance, is basically the length of this little thing. So, s of t plus delta t minus s of t is equal to the distance we have covered. Now, the t plus delta t minus t is the time during which we have covered. So, this basically gives us some kind of average speed during this time from t to t plus delta t. And if my delta t goes to zero, the limit of this, so this particular interval of time becomes smaller and smaller, the limit of this is an instantaneous speed at moment t. So, let me just put the word limit. So, that was our justification for introducing a derivative because this limit is actually a derivative of function s of t by t. Sometimes we do it this way, sometimes we do it this way. Different notation, but anyway. Now, this notation is a little bit more common place because it actually reflects what exactly we did. So, this is a differential, which is a limit of this infinitesimal variable divided by this infinitesimal variable. So, the d basically basically encapsulates in itself this fact of limit. So, these are concrete values and these are infinitesimal variables and we have a ratio. Now, let's recall another very, very long time ago, I had a lecture about harmony. Mathematicians do strive to have harmonious constructions. And one of the, well, obviously it's subjective, but I do think it's one of the very interesting properties of harmony is if you have moved from A to B, you have to be able to move from B back to A. So, the operation which does something, and in this case we have an operation of differentiation from the function s of t, we got the function derivative of s of t, right? So, this is operation from one function we derive another and obviously if we can move back from the derivative back to original function, that would make actually the whole construction more harmonious. And we did decide that this is an operation. It's called integration. I defined it in the previous lecture and that actually contributes to this harmonious thing. But now let's go back to the physical entity of this. Now, what happens in this case? If our average speed during this interval delta t is equal to, by the way, this thing obviously is delta s of t, right? It's an increment of the function. It's equal to increment of the function divided by increment of the time. Then increment of the function is equal to this average speed during this particular period of time delta t times delta t, right? From this, I derive this. Now, again, we're talking about physical sense of whatever we're doing. So far so good that this is an average speed during this time interval. Now, how can I construct the function s of t? s of t is the total time I have covered from moment zero to moment t, right? This one. And it contains many small intervals. So if I will divide this into small intervals, and on each interval I basically can do this, and then I will summarize all these small intervals, that would be my total distance, which I have covered, right? So basically, a sum of these would give me the total distance. Now, obviously, this is not precise because this is an average speed. This is an average speed during this interval. But if the time interval becomes smaller and smaller, and smaller, so the number of these little intervals is increasing, my precision of the result of summation of these things would be better and better approximating my real distance, which I have covered, right? So basically, we are talking about summation of something. If my delta t is converging to zero, so each one of these is infinitesimal, but the number of these will be growing into infinity, then my approximation to s of t would be better and better. So what did those people who invented the integration actually what did they do? Well, and primarily it's Newton and Leibniz as I was saying before. Well, they actually used this as a prototype for notation of the integration. So what they did is instead of this sigma, they imply that this is a sum of infinite number of terms here. So they used the letter s, but they stretched it very much and called it an integral. Now this is, obviously, as delta t goes to zero, this would be my instantaneous speed, which is actually a derivative, right? This is a derivative. And this becomes, instead of delta, they use g to indicate that this is infinitesimal. Basically, very similar to whatever we did here, right? So let me just replace this with this. And here we go. And this is now my exact distance. Well, obviously, later on they realized that to make this actually precise, you do have to add constant. We were talking about this before, but in any case, well, rather here, it doesn't really matter where I add it here. Now, what's the meaning of this constant? Well, basically, I would interpret it as the distance covered before my moment t is equal to zero from some other point. And obviously, this piece remains exactly the same. So in any case, I wanted to justify that this is not just, you know, somebody came up with this particular notation, as I was basically suggesting that let's just forget about the meaning of this, just accept it as a notation of integration. But actually, it does have this physical sense underneath. There is a basis for this. And the basis is this constitutes an instantaneous speed times infinitesimal interval of time. And if you will summarize the infinite number of infinitesimal variables that would actually constitute the original function distance as a function of time, which we started from. So consider integration as basically an operation which is delivering my distance based on speed. And obviously, it can be expanded to many other processes where it's not really like a speed, but something like a rate of change of something. And the result, so this constitutes the rate of change of something. And this is a result of that change during certain amount of time. So that was in the beginning of differentiation and integration as Newton and Leibniz primarily these two, and then our best and many other mathematicians. That's exactly what they put as a physical foundation of all these mathematical apparatus. Now, we cannot really say what was the physical or natural foundation for basic operations like addition or multiplication. We were just thinking about maybe people wanted to count something. But in case of integration and differentiation, we do have the physical need and real people who felt that this is the apparatus which they need to analyze mechanics of movement and any other rates of different processes which are happening in nature. So this is something which happened during our known history. It's documented. So there are real people, there is a real need for this and the real mathematical response to physical mechanical whatever and other natural needs. All right, that's basically all I wanted to say about integration. I wanted to put it on a certain more natural, more more physical foundation. So you do not really think about integration and differentiation as just two abstract operations. No, these are very much used in like everywhere in whatever we are doing, starting from just opening the faucet in the in the bathroom and ending with maybe spaceships everywhere. All these mathematical operations, integration, differentiation, etc., they're all used very much in our day-to-day life. That's it. Thank you very much and good luck.


Thank you. Thank you. I think identify yourself. Maybe I may be able to keep the questions to the next two. Other quality. EPA general press agency. Thank you for taking my question. As far as I understand, my question is regarding the designation of IA inspectors to Iran. As far as I understand, most of the core team of the experienced Iran specialists on your roster have been decimated by Iran's decision. So to what extent does have Iran's actions that lowered your ability to or take capacity to carry out meaningful and professional inspections in Iran? Thank you for the question. Let's take a serious blow to our capacity to do that. We of course continue. Of course we continue. But they have targeted inspectors who have a lot of experience in particular in enrichment and in other capacities. It takes a long time to prepare inspectors to have them the necessary amount to perform their work. We continue doing that. But it has it has constituted a a very negative development and a very serious blow to our ability to do our job to the best possible level. Yeah, it has. But we continue and we hope to reverse this decision as you perhaps know. Thanks DG, turn up in Tyrone with Bloomberg News. In your 2-2-3-1 report you mentioned specifically that the agency has not been able to verify Iran's total enriched uranium stockpile precisely any given day. And my question is that's a pretty serious accusation and it would suggest that there's a violation of the agreement. If that is the case why isn't that reported in the actual safeguards and if it's not a safeguards violation why are you including it in the report? Well, I agree with the first part of what you say quite obviously because you were quoting. I think your conclusion goes a bit too far that does not in itself constitute a violation but there have been problems. Just to confirm there's no violation but why are you not then able to verify the amount of material that's like your central job? No, we are doing that on occasion and in certain facilities there have been some problems or deficits but we are able it's not like we are not able we are inspecting all the graph facilities. Yes, I can confirm that. Hello, how are you? Thank you so much. I have two questions. Your recent report to the Board of Governors appears shorter than the last, the previous one. For example, you didn't mention about the quantity of enriched uranium in FTFP or no update on the EMD devices. Is this a message for warning to the Board of Governors to make a proper decision? Second question is, while according to the joint statement on 4th March between you and Iranian officials, the inspections on Iran facilities must be increased but it appears that Iran is imposing restrictions. Does the agency have the permanent access to the Iran facilities or not? Well, a number of things. What you refer to on the format and the length of the report is more a matter of clarity. On the contrary, you would say we are helping the Board. We noted that some of the reports were a bit confusing with many different amounts and information which, while being important, were not as clear as we wanted in focusing on the most important aspects that we wanted to report. It's a change of layout but not a problem in terms or a restriction in terms of the information we are giving. What you say, for example, about amounts in different facilities is something which we consider not to be important to be in the report because it's movement is very small amounts of material among the different facilities which, in any case, is captured in the general overall report. Also, in consultation with some of the member states, we were getting lots of questions and we came to the conclusion that it was a bit confusing. Frankly, it's a minor issue. Your second question is there are restrictions, of course, in the sense that Iran has ceased to implement lots of aspects and nuclear related obligations under the JCPOA and it's not implementing mutually agreed additional measures under the joint statement of March 4. When it comes to the CSA, when it comes to the comprehensive safeguard agreement we do implement it in full. Thank you. A couple of questions if I may. First of all, back to the de-designation of inspectors, I was hoping we could get a little more clarity on the numbers perhaps because we've had there was the statement you issued when you first were notified of this. It was a bit awkward, it was something like a third of the most experienced core of your inspectors. It seems to me what we're dealing with here is enrichment specialists who are on the Iran team and have a lot of experience with Iran so what proportion of those people of that team has now been removed just to give a clear sense of what's going on. Secondly, on the joint statement there's no progress at all on the joint statement. Do you regret suggesting agreeing to and announcing an agreement that was so vague that there were many, many questions about it at the time and that you said yourself at the time would be subject to future negotiations. Was that a mistake? Given that at the time it removed pressure on Iran and basically meant that there wasn't a resolution meeting which has since pretty much become an impossibility for other reasons. Yeah, on the issue of the de-designation I think and I think you François you quoted yourself it's a good number of people we don't want to get into specific numbers of our names for obvious confidentiality reasons but when we say it's a third of the most experienced core group it gives you an idea and in my answer in my previous answer I aimed at that it's not a small thing it's something which is affecting our work while not preventing it as I was saying it's really meaningful it's not a detail. This is why I have chosen as you may have noted to go public with it and to be very, very firm and to engage with Iran and to tell them what I believe this is completely uncalled for this is completely illogical and I have said and I say to you in the same way I've said this to them we have engaged I should say the Vice President has replied to me and we are having a conversation on these issues or perhaps we can improve the situation. Regarding the joint statement I would never regret trying to find solutions never, ever and let's not forget that the joint statement the joint declaration has started to be implemented what we are alluding to is the fact that it has been frozen by Iran as of in relative terms May we were able to reinstall a good number of cameras we also reconnected some online measuring equipment all of them now is EMD it's the same basically we have been able to calibrate them we have been able to service the cameras so all of that I think is important so by no means this document when you really it has a number of commitments for as long as Iran does not go back on them they must work with me on the implementation of the statement Iran I would not regurgitate what Iran has been saying maybe you should ask them but they consider that for them to be more cooperative other things should happen which exceed the IEA thank you very much I just want to ask a different area as you know right now ongoing war in Middle East between Israel and how much of Gaza from Israel it's like they trade the people of Gaza using the nuclear weapons actually it was every time discussion about the Israeli capacity be Israel has a nuclear weapon or not but after that this discussion increased I would ask your point of view what do you think about it are you concerned and the second question because of the current situation would you ask or call the Israeli authorities to accept safeguard agreements and to be part of parties I would start with the last part of your question because it's the easiest I've already had not only myself the General Conference the Board of Governors I think have been repeated calls for all countries in the Middle East and this includes Israel to join the NPT and to open all their nuclear facilities to comprehensive safeguards inspections and this is very clear so I don't need to do now I can do it now for you and I repeat every country in the Middle East should be a party to the NPT which is the most successful treaty in arms control and operation in history so we have to do this the other thing in general and I will not elude your question I think you know me by now I always answer everything you ask me but you also know that I don't like to comment on some other people's comments which may include what you refer to but let me say one thing which is very very clear I think in the world in general there is a wide agreement on the fact that a nuclear war cannot be won and therefore should never be fought and any loose talk about using nuclear weapons is at best unacceptable I think I answer your question Thank you very much for the questions Please come to the side with Efe a question related to your nuclear industry in your home country with you President has announced a cut in the public investment in general terms research and investigation also he denies the human origin of the climate change the question is climate change how these political views could affect the development of the nuclear industry in Argentina taking this sector that needs not only the financial support from the state but also the control and also the fight to tackle climate change thank you thank you very much irrespective of the fact that it's my home country my approach is the same regarding views and opinions from high officials presidents or heads of government Javier Millay has won the elections he's the elected president so we will see what he does when he assumes office I will be in Buenos Aires in December so perhaps I will have an opportunity to talk to him and to get an impression of what he intends to do on that he's not the president yet you're not especially worried about what will happen thinking whether he views on this the position of the I don't think as a candidate he has referred to the nuclear plan in Argentina which you said is in general public investment but like I said I shouldn't be having opinions on national matters of internal policies when it comes to my own country and other countries I interact with heads of government on issues of mutual interest and as I said I hope to be having a conversation with him perhaps in December if he has time to see me any other questions Hi D.G. Markusil from the NICA I have a question regarding the regulatory budget the regular budget and the outstanding contributions which have gone down quite a bit since the general conference but are still quite high and I was interested how much of an impact does this have on the agency and have those countries that are reluctant with their contributions approached you and voiced any reasons for why they delay their contributions or is there anything with regard to the agency it has been a very serious matter this is why I came to you you remember we discussed that in my last press conference and of course before doing that I went to the board of governors because we were really running out of money which have not happened in such a dimension to this agency since the 1990s I believe or even earlier so ever since that happened there were a few mitigation measures that were taking some countries paid some money even advanced contributions corresponding to next year because I think many many countries care a lot about this organization and keeping it functioning because of what we do around the world the situation is slightly better now I think we will make it to the end of the year there will be some impact on the activities in particular in the technical cooperation program in the first part of the year perhaps due to these delays but I hope that by the end of the year we will have received all access contributions but I was very very concerned I asked the governors just now in the morning to make you know every possible effort so that we do not have to see a situation like this ever again. Sorry I'm playing completely different. Has Saudi Arabia now informed you of its plan to rescind its small quantities and switch to a CSA? They informed me orally the minister of energy indicated that to me orally and I'm going to be continuing discussions with them I might be visiting the country soon. Orally that's it. Orally, yes. Back to Iran the Iranian nuclear chief Islamic today said that Iran is pushing ahead with building its second nuclear power plant in southwest of the country and in the coming days the groundwork for the main reactor building would be started. Has Iran informed you adequately about its, has Iran been informing you adequately about its plans with this nuclear power plant because they have been trying to understand they have not been implementing all their you know usual information requirements? Yeah we don't, we haven't seen problems with regards to this facility or planned facility the issues in the jargon we call 3.1 refer more to other types of facilities as you know more sensitive facilities but not to a civilian nuclear power plant. Although sometimes you know what happens is that countries announce plans to build nuclear power plants and you know that's a bit. And until until they do it there are some administrative delays but we don't see that thing as a source of concern Thank you very much for your interest Thank you


It's a pleasure to be here and it's a joint work with Iqmar and with Band Puhala from Ahen. So in the last talk you have seen multiplayer games and this is somehow a follow up for the general motivation which is to get some understanding of multiplayer games and in this talk for multiplayer games with imperfect information. And I think Roma has given enough motivation for this. So multiplayer games are a great model, very powerful. They arise in economy and biology and we were many of these games are games with imperfect information but the price for this powerful model is that computationally these are very difficult games to study, very difficult to solve. So some of the issues you maybe know are so in multiplayer games it's really difficult to say what does it mean to win. So in the last talk they studied Nash Equilibrium. This is one notion of winning but this is just one of possible notions and you might ask which Nash Equilibrium what do you really mean by winning. But then when you add imperfect information you also have this problem. So how do you describe it? What does it mean that a player knows something and then there is the next problem. So what does the player really need to know to play good? So for a Nash Equilibrium if whatever I do I lose terribly then maybe I don't need any knowledge. So these issues come together and we try to somehow separate them a little bit. So we wanted to focus on the issue of imperfect information and that's so we decided to study a special kind of multiplayer games where you have n players but they all want the same thing. They have just one goal, a common goal for all the players and they have to enforce it against nature. So against one adversary who knows everything has perfect information and can do everything. And so this problem maybe directly reminds you of distributed synthesis and that's why we named the games distributed games. So let me introduce them a bit more formally. We have n players and nature and then each of the player has a set of actions, a finite set and the common action of all players. We denote the set A, it's just an action profile where everyone makes an action. So now the game we describe it as a graph where the nature resolves the non-determinism. So there is a move relation and the information of the player is given by equivalence relations for each and every player. So here is an example and you can see well the notes of the graph, the action profiles of two players on this graph. So from the first note both players can just take the bottom action and the nature chooses one of the four successors and then afterwards the player chooses some actions and then the equivalence relation for one player is drawn as dashed lines. So one player cannot distinguish this A0 note from A1 or end B0 from B1, they are indistinguishable and then I don't know if you can see the other equivalence relation which is dotted. So the other player cannot distinguish A0 from B0 and A1 from B1. So please think that there is an equivalence relation here and here. So two equivalence relations and now a strategy for a player is a function from sequences of notes from the play giving an action and it has to obey the information meaning if two histories are indistinguishable for the player it has to give the same action. So now I want to look at this example game in a bit more detail. So the idea of this game is that one of the players can only see the digits and one of the players can only see the letters. In the first move it's the nature that chooses both the digit and the letter. Oh yes, I think that's better. And then in the next move it's the player who chooses and the player 0, the first player chooses a letter and the other player chooses a digit and all the way one player is informed only about the letters that have been played and the other player is informed only about digits. So the strategy of one of the players is after seeing a sequence of digits of which I generate every second and every other one is generated by nature, I play a digit and for the other player it's the same but with letters. And now the winning condition for this game, so the play is a sequence of pairs, letter and a digit as you see in these notes, first generated by nature, then by the strategies of the player, then we go back to the top node, then again we have a letter and a digit generated by nature, then again by the strategies of the players and so on. And then the play is won by the coalition of all players if the sequence belongs to a let's say regular winning condition and the question we ask is can we find a winning strategy profile? And then this example is good because it's relatively easy to see that you can take a Turing machine and construct a winning condition W such that the players will be winning only if they can construct a halting run of the Turing machine. So this is just to make this first remark that this problem in general is undecidable, it's a well-known thing from distributed synthesis, so if you can do something like this, split the two players and make them play, you cannot hope for decidability, but the thing we want to do is we want to look a bit more into why does this happen and what is the information the players have and maybe for what kind of specific winning conditions can we do better? So what can be done in this setting in general? So to have a better understanding of what is the information the players possess in each step, we will track what they know and to have a description of the knowledge of the players or what they think they might know or what they think their opponents know and the players they play with and what other players know, they know, they know about them and so on. We will use Kripka Structures epistemic models which consist of a set of nodes connected by equivalence relations. So for every player we have a relation telling which situations which world are undistinguishable and our epistemic models are related to the game at hand, meaning every node in the epistemic model has an associated vertex of the game because this node represents a position which is in this point in the game. So for example, in the game I presented you here, this first row is actually this epistemic structure, right? There is one player who knows whether it's an A or a B and another who knows whether it's a zero or a one. That's somehow the situation after the first move in the game. Now let's say we arrived at a situation which is described by such an epistemic model. So we ask what is the next knowledge of the players in the game? What's the next epistemic model? So since we consider all of these states possible and let's say we have a fixed action profile for the players. So from each and every of these state you take an action, the action prescribed by the profile and then the nature might choose a number of possible successors. So the epistemic model grows by splitting each and every vertex into the possible successors the nature chooses. So here is a definition. As you see, if you want to compute the next epistemic model, you take a position of the one you start with and take all possible next vertices. And then the label link is as it should be with vertices and the equivalences are what you can distinguish, you do distinguish. Now it might happen in this definition that you arrive at two epistemic model which are not connected by the sum of all equivalence relation which means they are distinguishable for all players. And these we will consider as separate positions because in everybody in our coalition already knows we are somewhere else, we can safely think it's another position. And then given a game and starting vertex, we will unfold this construction. We start from a vertex, it's a one-note epistemic model and we unfold it. Look at the next epistemic model and the next one and the next one, so on. So here is a formal definition but let's look at this example game we had. So let's start at x. So this is our first epistemic model. This is the next one. Then since the players just chose their letters, well this is just one of the possible next models. They could have chosen in all of these possible states a different letter, right? So this is just one of the models. And now the game goes back to the top and then the nature makes the choice again. This is another step. Now you can see one of the players knows that it's a zero, that it was 0-0 or 1-1 or 1-0. But he has to consider all the options for the other player. And in this way these models simply grow and grow and grow. This cannot be avoided. So this epistemic unfolding of a game, here is the complete view. You start with a single epistemic model, unfold this position and so on. Now one thing to note is in the game you had just a set of actions for each player, a finite one. In this epistemic unfolding on every level here when the players choose an action I mean they choose an action profile for every vertex in the model. So now the branching of this game grows. At every level it's bigger and bigger. So it's a bit of a weird game, a game not with a fixed finite set of actions but with a growing or infinite one. But still it's a finitely branching game. And this is a game of perfect information. So in this way by simply collecting the knowledge of all players we unfolded a perfect information game to an imperfect information. Now okay the theorem you might expect is the following. If the grand coalition has a winning strategy in the original game it has a winning strategy in this perfect information unfolding game and vice versa. And the proof of this theorem is not very surprising. You track the strategies to look at a few technical things. Now the problem of course is that this unfolding, this tracking is an infinite structure. So we have taken maybe an undecidable game and built an infinite one which is a simple game, a perfect information game. But what we would really like to do is for this tracking game to be at least manageable for simple cases. Maybe the example we had, maybe you can't do much, it's undecidable in general but at least for one player games this should not be so big. So here is an example of a very simple game, just one player and the information sets grow and grow while this is actually not necessary. You could just store the set of notes where you are and that's the only thing you need to know. So to correct this problem we will quotient the Kripke structures by homomorphic equivalence. And now just to remind you, I think this was luckily already introduced today in the invited talk. So two models are homomorphic if there exists a function which, so if there is a label in the first one there has to be one in the next and they are homomorphically equivalent if there is a homomorphism from one to the other and a homomorphism from the other to the first one. They don't need to satisfy anything else, they just have to exist. And the core of a model, the core of the Kripke structure is a homomorphically equivalent structure with the minimal number of elements and now it's first of all not clear whether there is just one or maybe many structures with minimal number of elements. But in fact you can prove a theorem that there exists a unique core for every graph and for every epistemic model as well. And so just to give you an example we had this structure, this square with two equivalence relations and the core of this if the labels are the same is just one note, right? The homomorphism on the one side everything falls here, the other hand you just embed. Okay, so now the idea now is to take the epistemic unfolding we had and quotient every structure that appears there by core. But this epistemic unfolding is a game, it also has edges and it has a winning condition where you have to look at the paths through the place. So now when you just quotient it wouldn't be clear where the path should follow. So the actual definition is a bit more involved, so we take the definition again and then say from the next step model you make the move and then you quotient. It's just a technical thing to make sure that you can follow the place through the models because well when is a play in now winning, a play is a sequence of Kribka structures. So it's winning if all of the small plays through the sequence were in the old winning conditions. Now what does it mean a small play through the sequence? Well previously it was quite clear, it just means it's connected with the edges. Now you have to look at this homomorphism which comes from the core. So we go to the next state and then the homomorphism tells you where to go. So the winning condition is a bit involved but that's how you define it. So now when we quotient by core by actually by any homomorphic equivalence we get indeed much smaller tracking games. So let's get back to this example again. We start from the root. So as you've seen this is the next structure and then when we get back to the top we had this structure previously and then it grew to the larger grid but now since we quotient by core we actually don't get this structure but simply the root. So I've drawn the loops, they've been there all the time, right? These are equivalence relations meaning they are always there. Well and then from here we get back this structure and so on but that means in fact we repeat a cycle here, right? Okay then there are some other site possibilities but all in all we get a finite perfect information game. So this means a game we can solve. So as you can see there is probably some problem with undecidability but the theorem so the theorem will not be as general as the previous one. So the equivalence now will only hold for observable winning conditions. And an observable winning condition you can think of it as one given by a labeling which is seen by all of the players. Alternatively if you look at the information structure it is something which is uniform on all of these connected crypto models. Meaning if there is a color, a label it's the same for the whole structure in the state. It doesn't depend on the particular node. So for observable winning conditions our theorem is the grand coalition has a winning strategy in this original game if and only if it has a winning strategy in this core unfolding. And now the proof idea is again to translate strategies but the tricky point somehow starts at the moment when you quotient through the core. So imagine there were some plays we played played and there was one play going to this node and another going here. And now maybe the winning strategy for the whole game decided to do one thing here and something entirely different here. Because the information that well maybe we are somewhere else maybe one player really uses the fact that he knows something important here. And does something really different in the core. Well we have put this all together so we will choose just one of these possibilities. And now why so for example this play would be if someone played here and then continued playing this way. Well somehow the play has been cut and changed. Why is this still OK because we can find some play that would be this one in this case. Which goes through the same Kripke structures through the same sequence of structures. And well this small play was winning by assumption. So the coloring of the sequence of Kripke structures is right. And this gives us the result that since the condition is observable we just care about the sequence of structures. And well that does the play in the core is winning as well. OK so what can we what results can we derive from this construction. So it's a bit of a general construction but does it imply something. So one previously known result is that when the games are hierarchical. Meaning that one equivalence relation is a subset of another and the subset of another and so on. Then one can solve games of imperfect information of this kind. And indeed if you just look at what kind of Kripke structures can you get if the relations are hierarchical. Then it turns out if there are n players and the hierarchical structure of equivalence relations. They're at most n fold exponential so two to the two to the two n times. Many Kripke structures of this kind. Which means the quotient by core of any game of any hierarchical game will be a finite graph. Which gives us this corollary that hierarchical games with observable winning conditions. For such games the question whether the grant coalition has a winning strategy is decided. So this this lemma is actually just need to count and then you get this corollary for free from from our result. OK so that's basically it. I think the notion I really want you to remember from this is the epistemic unfolding. Which you can do for for every n player games with imperfect information. But for observable winning conditions you can quotient it by homomorphic equivalence and it will still be OK and much smaller. And of course there are several open questions here. So one question is definitely if the games are not coordination games if there are many winning conditions. You can do the same construction but what should you look at what are the results. But maybe even a more interesting question is for example hierarchical games can be solved even for non observable winning conditions with automata methods. So can we can we solve them as well with quotients. Maybe we should use something else than a core maybe some other homomorphic equivalence. And what we suspect now is more than maybe for every regular condition you should use a different quotient. So maybe there is one good for every condition but maybe not one good for all of them. So this is something for for future work and I think that's it. Thank you.


Is your site usable? This module is made available to you through a joint initiative between the Legal Services National Technology Assistance Project, the Legal Services Corporation, and Idealware under a Creative Commons by-license. Why should you prioritize usability when there's so many things to do? If you think about what you hope to accomplish with your site, such as identifying those that need further help, providing helpful information, getting more volunteers or more donations, all of those goals are helped by a usable site. Your website represents you. If you present a face for your organization that is, say, hard to use and hard to interact with, then people will think your organization itself is puzzling and baffling. Not that we are saying that's the case with the Legal Aid Society presented here, but creating a website that is usable and valuable to your audiences should be one of your overarching objectives. It sounds easy. Make your website usable. But for whom? Are you looking to help those who want representation or to get volunteer lawyers? You can be a lot of things to a few audiences, but trying to be everything to everyone will just make your site confusing. As we talked about in the Goals module, it's important to think about what your users want to do on the site. It's easy to think in terms of your mission. Well, for us, everyone comes with a complex legal problem. And while some people do, as many might come to find your phone number or find out whether you can help. Users are often looking for tactical information, so make that information easy to find. Most of the time, people have what they think is an easy question, and they are looking for just a simple answer. That's not always easy to do, but it's important to keep in mind. The idea here is to balance your goals with your visitors to make sure that your visitors can get what they need while you encourage them to do what you want them to do. If the idea behind your website is to encourage those who need legal help to come in and visit with you in person, then you're going to want to put the information to do that front and center. On the flip side, if you really want them to self-serve, whereas they want to come in and talk to someone, make it easy for them to start using your self-help resources. But don't fight your users. If you know they're going to want a way to call you, give them something that at least lets them know that they can't call you, as opposed to just not giving your phone number. How can you be sure that your web visitors will be able to find what they need? The elements in your navigation summarize your site and tell people what you have there. When people look for a page in the menu, you'll want them to feel that it was intuitive and felt fast and easy to do. To do this, provide straightforward navigational labels for them. Think about the navigation as a directory of your services. This one is from Iowa Legal Aid. It's worthwhile to spend time selecting labels that are meaningful to your users. Simpler and specific terms are always better than complex or vague ones. The homepage itself is another critical piece to usability. It is not the only driver of usability, but it is an important one. The homepage sets expectations as to what there might be on the site. On the page we're showing you now, one might think, oh look, I can get information about disability, education, and work topics. If I come in and I'm being evicted, however, this homepage would create the impression that housing issues aren't covered. But of course, you can't put everything on your homepage. Instead, the key is to succinctly summarize in plain language what you do. It's also critical to remember that not everyone will scan your site for information about what you do. Some people will jump right into a search box, so it makes sense to have that as well and to make sure it works. If you don't prioritize and everyone in the organization throws a whole bunch of things at the homepage, what you get is a very ineffective and confusing page. In contrast, the Illinois Legal Aid Society presents a very clear set of options. Do you want legal aid help? Are you a legal aid attorney?  Find a finite number of things you want people to be able to do on the homepage and make those your options. It actually doesn't matter if your audiences have to click through many pages to get to the information they need if each click is easy and obvious. What matters is that they're confident they're on the scent of what they're looking for. Scent is actually a usability technical term, believe it or not. How do you know if people will feel they're on the scent? User testing is really helpful, and we'll cover that in a bit. We would be remiss if we talked about usability without talking about the content. It doesn't matter how easy it is for a person to get to the information about what to do if they are being evicted, if the information presented is unclear or 50 pages long with no paragraph breaks. You want to make sure that people understand what services you provide. It's obvious to you, but you want to make it very clear to your visitors. For example, Pine Tree Legal Aid greets visitors with this message. Put yourself in your user's shoes. From their point of view, they don't want to know everything, just, well, the one thing they came to find. It's much harder to find that one thing if there's tons of unscanable text. Obviously, your website can't read their mind to figure out what that one thing is, but you can get closer. What are the 10 things that they're most likely to want to know? What do they need to make a decision? You don't need to tell them every detail right away. How do you present those 10 things? Lots and lots of text is much worse than presenting information succinctly. Keep your paragraphs short. Put the most important thing first in the paragraph. Write your content, and then cut your word count in half. Use lists and bullet points to break up long paragraphs. Most people don't read every word of text on a website. Rather, the research shows that they scan the page for the information they're looking for, or they scan until something catches their eye. Breaking up paragraphs into lists will help people scan the page. Links directing users to content about specific topics can be easier to navigate than trying to fit all the information on one page. This would be a good strategy for a home page, where you can provide links to draw people into other parts of the site. Images and video can help explain topics on your site for people who may have more trouble reading or understanding English. Keep accessibility in mind, though. Not everyone can see images or a video. We'll cover that more in the accessibility module. We've looked at a number of best practices for usability. You can run through a checklist to think about navigation and content, but there's nothing as useful as actually talking to people. You can ask people, or you can evaluate the data that's available to you by conducting user tests, sending surveys, or reviewing your site's web analytics. User tests are easier and more useful than most people think. Tests show how your theories of usability work in the real world. Usability experts don't say, I know what I'm doing, therefore I don't need to user test. Instead, they say, I know what I'm doing because I user test. How do you do it? Define a few things that you'd like to see if people can do on your site. Next, recruit three to four people from each target audience you'd like to include. Sit each person down at a computer. Ask them to talk aloud as they look at your site and attempt to complete a task. Their thought process will give you unexpected insights and information about where they get slowed down or stumped by your website. If they stop talking, your key question should be, what are you thinking as you look at this page? You could plan the task in advance, or ask them to think of one on the fly that allows them to explore on their own terms. To get buy-in to fix the problems that the usability test will uncover, and trust me, you'll find things. It helps to record the user tests and show them to your management staff and board. Set up a video camera to record, or record the screen and an audio track. Playing it back for people can be a great way to get buy-in from your organization, especially from those people who would say, no one could confuse those things, or everyone knows what that means. User testing or interviews are very good if you want detailed information about what things might be problematic. On the other hand, if you want a lot of people to answer a few questions, a survey can be helpful. You might ask them if they found your website to be helpful. Simple things like, what's your purpose on the website today? Or, did you find what you are looking for? We'll give you a sense of what people want to do on your site, and what their experience was like. Online survey tools, like SurveyMonkey, will make creating online surveys, or ones that pop up on your website itself, a straightforward process. Web analytics are also useful for figuring out what people want from your website. Install Google Analytics, if you haven't already. You'll need someone with some website savvy to do it, but it shouldn't be a large project. After it's set up, Google Analytics will begin to provide numbers, charts, and graphs about your site. What are the most popular pages? What paths do users take through the site? How do visitors come to your site? What page did they enter the site on? If it wasn't the home page, you can ask yourself, will they be able to find what they came for? To sum up, the core of usability is to define, usable for whom, to do what? Most people default to navigation when thinking about usability, but it's also important to think about the content and the way you present it. If you're concerned about the usability of your site, user testing is often more straightforward than you might think. There are plenty of usability resources available to help. Steve Krug's Don't Make Me Think is a terrific book, and the User Interface Engineering Library covers many, many topics. The Nielsen Norman Group provides tons of information from Jacob Nielsen, one of the most well-known usability researchers.


Hey, this is Brett, and this 2016 Chevy Colorado Extended Cab Short Box is stock number 13503Z. I am here at Summit Automotive in Fond du Lac, Wisconsin, your new and used light duty truck headquarters. This 2016 Chevy Colorado has the 3.6 liter V6 engine, puts out 305 horsepower. This truck has been fully safe and inspected by our service shop, has a fresh oil and filter change. All the fluids have been checked and topped off and it is 100% ready to go. I'm going to go all the way around in this video, inside, underneath, start it up and take a look under the hood. Black clear coat is the color and I shoot all my videos in 4K, so if you have HD capabilities, turn them on now because it is your best way to check out the quality, condition options, and cleanliness of the vehicle before seeing it in person.  Front fender is in very nice shape as well. If you like the video, you can subscribe to my YouTube channel, which is youtube.com slash summit auto. Click the bell notifications and you'll get updates every time I do the videos of our new and used inventory here at Summit. This one comes with the painted 18 inch alloy rim wheels and it has Falcon Wild Peak 265-60 R18 tires and they have probably about 60-70% of the tread left on them, frame and underbodies in pretty nice shape. And coming around the front of the vehicle, this one does have some LED headlamps and LED fog lights, front bumpers in really nice shape. We'll turn all those on at the end of the video. It also has some LED highlights up there, so we'll turn those on at the end of the video as well. The hood's in really nice condition, passenger side front fender, I didn't see any major dents or dings on there, and the passenger side front wheel, no major scuffs or scrapes. As you go down this side of this 2016 Chevy Colorado, take note of how clean that body is, how reflective and mirror like that paint is. I take these HD videos so if you are far away or even if you're close by and you just cannot make the trip down, but you're still interested in purchasing the vehicle, you can see the truck, hear the truck, and have confidence in the vehicle that you're looking at before you even get here. So when you do get here, there's absolutely no surprises and you can make a smart and informed buying decision from wherever you're at. Back wheel is in nice shape, and the back tires have just as much tread as the front tires. Once again, frame and underbody, looks pretty good. And if this video helps you make that buying decision like your salesman know that you saw the video, that it was helpful and that brought it to you. Pretty nice under there, not too bad for a 16, comes with the nice factory painted step bars, has this racer back bar system that holds those lights up. Rear bumper is in nice shape, it does have the rear bumper steps, the locking tailgate. It also comes with a tonneau cover, however because of that bar system up there, it will not go on. So if you wanted to put that on, you'd have to take those bars off. Get some side box tie downs and get a very nice spray and bed liner back here. Tailgate shuts nice and solidly. And for full disclosure, this back wheel is in excellent shape as well. Once again, down the rest of the side doors and cab all look really good. It does come with the power mirrors with driver side blind spot mirror.  You get the bucket seats in the front, no rips, no tears, no stains, very nice clean seats. Power driver seat, factory floor mats, it does have auto headlamps turned out, four wheel drive. Those are to turn on those LED lights, the highlights. Power windows locks and mirrors, back seats are in pretty nice shape. Not a ton of room back here, but it would work in a pinch. So these seats fold up and there is a little storage under there.  Does have the VIN sticker right there and then the tire and loading information sticker is right there. We'll hop inside, check out the miles, the radio, and everything that this truck has to offer on the interior. You can see that this one has 43,803 miles, instrument cluster is very nice and clean. Comes with the leather wrap steering wheel. There's controls on the left, Bluetooth and information center controls on the right. This one has the Chevy MyLink radio, AM FM and Sirius XM radio capabilities on there. It also has a projection manager where you can project your cell phone to the screen. So while this one does not have the NAB system, from the factory you can project your cell phone up there with Waze or Google Maps and then it's like you have Navra on the screen so that's a pretty sweet system. Down here your climate controls, radio controls, stability control, that's for your cargo lamps, has a tow mode, Augs and USB, and then here is your automatic transmission shifter, which is a nice shape. Passenger side, floor mat and seat are in excellent condition, the headliners in very nice condition, smells very clean inside this truck and you get map lights up there as well as on-star in SOS buttons in the living room there. We'll start it up and take a look under the hood. That's right up, no check engine lights or anything like that. I would personally like to thank you for checking out the video today and hopefully from this HD video you've been able to verify the quality condition options and of course cleanliness of this Colorado inside and out. Those LED lights are extremely bright and the highlights up there are working nicely. Once again under the hood we have the 3.6 liter V6 engine, engine bays very clean runs very smooth, 305 horsepower, once again this truck has been fully safety and inspected by our service shop as a fresh oil and filter change, all the fluids have been checked and topped off. There is the emissions sticker, shocks are doing a nice job holding that hood up and I would highly recommend this truck to make quality and condition standpoint and to see more pictures of this truck or one of our 550 new and used cars, trucks, SUVs, minivans, trailers, halftones, quarter tons, one tons, colorados, rangers, you name it, we've got to go to that website right there, summitauto.com, full pictures and descriptions of every single vehicle from two locations all at summitauto.com and if you'd like to check out more HD videos you can go to youtube.com slash summitauto remember to like, subscribe and share on this video and all the videos that you see there, click the bell notifications to get updates on the videos I do each and every day here at Summit Auto. Back in a second you'll see a link to subscribe to my YouTube channel on the upper left to link to more Colorado trucks I've done in the upper right, a link to this vehicle on our website on the lower left and a link to one of our latest YouTube videos in the lower right. Click those, check us out and we're super excited to help you with this ultra clean 2016 Chevy Colorado extended cab short box LT in black clear coat. Thanks again for checking out the video, remember to like, subscribe and share on the YouTube channel. I really appreciate it. Thanks again.