Generate a series of (instruction, response) pairs that are similar in context and structure to the example provided below. Each pair should consist of a concise instruction followed by an appropriate, detailed response. The instruction should pose a clear task or question, while the response should provide a comprehensive answer or solution that could be understood by someone with a basic understanding of the subject.

Example pair: 
Instruction: Source text:
At its simplest, forex trading is similar to the currency exchange you may do while traveling abroad: A trader buys one currency and sells another, and the exchange rate constantly fluctuates based on supply and demand.

Currencies are traded in the foreign exchange market, a global marketplace that’s open 24 hours a day Monday through Friday. All forex trading is conducted over the counter (OTC), meaning there’s no physical exchange (as there is for stocks) and a global network of banks and other financial institutions oversee the market (instead of a central exchange, like the New York Stock Exchange).

Featured Partner Offer

A vast majority of trade activity in the forex market occurs between institutional traders, such as people who work for banks, fund managers and multinational corporations. These traders don’t necessarily intend to take physical possession of the currencies themselves; they may simply be speculating about or hedging against future exchange rate fluctuations.

A forex trader might buy U.S. dollars (and sell euros), for example, if she believes the dollar will strengthen in value and therefore be able to buy more euros in the future. Meanwhile, an American company with European operations could use the forex market as a hedge in the event the euro weakens, meaning the value of their income earned there falls.

Summarization request:
Briefly summarize how forex trading works and who the major players are.
Response: Forex trading involves exchanging one currency for another. The value of currencies fluctuates constantly based on supply and demand as well as economic factors. Most forex trading is done between large institutions like banks, fund managers, and multinational companies. These major players speculate on the strength of currencies or hedge against changes. They don’t usually take physical possession of the currencies.

Your task is to generate more pairs that maintain this level of clarity and detail. The topic is Summarization. Write a long text of instruction by yourself, then summarize the given instruction in a response. Ensure that the responses are informative and accurate, suitable for an educational context. 

Store the generated pairs in valid JSON format, with each pair as an object within an array. Each object should have two key-value pairs: "instruction" and "response". For instance: 

{"contents": [{"instruction": "text", "response": "text"}, {"instruction": "text", "response": "text"}, ...]} 

Remember to maintain consistency in the format and ensure the generated pairs are diverse and cover a broad range of subjects. You must return the response in the asked format and you must not add any additional text in your response.

Source text:

Extractive summarization is a technique used to create summaries by identifying and extracting the most relevant sentences or phrases from the original text. This approach assumes that the important information is already present in the source document, and the task is to select the most representative sentences or phrases that best convey the essential meaning.

One common method for extractive summarization is sentence ranking, where individual sentences are scored based on various features, such as word frequency, position in the text, presence of keywords, or similarity to the overall topic. The highest-scoring sentences are then extracted and combined to form the summary.

Another approach is based on graph algorithms, where the text is represented as a graph with nodes representing sentences or concepts, and edges representing the relationships between them. Centrality measures, such as PageRank or TextRank, are used to identify the most important nodes (sentences) in the graph, which are then extracted to form the summary.

Extractive summarization has several advantages. It preserves the original wording and style of the text, ensuring that the summary remains faithful to the source material. Additionally, it is generally faster and more computationally efficient than abstractive summarization techniques, which require generating new text. However, extractive summaries may lack coherence or fail to capture complex ideas that span multiple sentences.

Summarization request:
Explain the concept of extractive summarization and discuss its advantages and limitations compared to other summarization techniques.
user
Extractive summarization is a technique that creates summaries by identifying and extracting the most relevant sentences or phrases from the original text. It assumes that important information is already present in the source document, and the task is to select the representative sentences or phrases that best convey the essential meaning. Common methods include sentence ranking based on features like word frequency and position, or graph algorithms that identify central sentences based on their relationships. Extractive summarization has the advantage of preserving the original wording and being computationally efficient. However, it may lack coherence or fail to capture complex ideas spanning multiple sentences compared to abstractive techniques that generate new text.
assistant