{"action":"created","issue":{"url":"https://api.github.com/repos/snu-sf/pl2015/issues/160","labels_url":"https://api.github.com/repos/snu-sf/pl2015/issues/160/labels{/name}","comments_url":"https://api.github.com/repos/snu-sf/pl2015/issues/160/comments","events_url":"https://api.github.com/repos/snu-sf/pl2015/issues/160/events","html_url":"https://github.com/snu-sf/pl2015/issues/160","id":88730667,"number":160,"title":"\"Gamma\" in STLC","user":{"login":"AdamBJ","id":8980400,"avatar_url":"https://avatars.githubusercontent.com/u/8980400?v=3","gravatar_id":"","url":"https://api.github.com/users/AdamBJ","html_url":"https://github.com/AdamBJ","followers_url":"https://api.github.com/users/AdamBJ/followers","following_url":"https://api.github.com/users/AdamBJ/following{/other_user}","gists_url":"https://api.github.com/users/AdamBJ/gists{/gist_id}","starred_url":"https://api.github.com/users/AdamBJ/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/AdamBJ/subscriptions","organizations_url":"https://api.github.com/users/AdamBJ/orgs","repos_url":"https://api.github.com/users/AdamBJ/repos","events_url":"https://api.github.com/users/AdamBJ/events{/privacy}","received_events_url":"https://api.github.com/users/AdamBJ/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2015-06-16T13:38:01Z","updated_at":"2015-06-17T05:38:08Z","closed_at":null,"body":"Can someone help me better understand the concept of gamma as it applies to STLC? Here is what I understand: gamma is related to type, and somehow maps each of the variables in a term to a type which allows us to determine the overall type of the term. I'm a bit confused about the specifics of how it accomplishes this though. Also, I don't understand some of the auxiliary functions related to gamma such as ```extend``` and ```extend_neq```. What do these functions do and how are they related to the gamma of a term?\r\n\r\nThanks"},"comment":{"url":"https://api.github.com/repos/snu-sf/pl2015/issues/comments/112658005","html_url":"https://github.com/snu-sf/pl2015/issues/160#issuecomment-112658005","issue_url":"https://api.github.com/repos/snu-sf/pl2015/issues/160","id":112658005,"user":{"login":"justlaugh05","id":9108550,"avatar_url":"https://avatars.githubusercontent.com/u/9108550?v=3","gravatar_id":"","url":"https://api.github.com/users/justlaugh05","html_url":"https://github.com/justlaugh05","followers_url":"https://api.github.com/users/justlaugh05/followers","following_url":"https://api.github.com/users/justlaugh05/following{/other_user}","gists_url":"https://api.github.com/users/justlaugh05/gists{/gist_id}","starred_url":"https://api.github.com/users/justlaugh05/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/justlaugh05/subscriptions","organizations_url":"https://api.github.com/users/justlaugh05/orgs","repos_url":"https://api.github.com/users/justlaugh05/repos","events_url":"https://api.github.com/users/justlaugh05/events{/privacy}","received_events_url":"https://api.github.com/users/justlaugh05/received_events","type":"User","site_admin":false},"created_at":"2015-06-17T05:38:08Z","updated_at":"2015-06-17T05:38:08Z","body":"Think of states in the previous chapters. extend would be like update. empty Gamma would be empty_state. Instead of holding values of variables, it holds the Types"}}