Lesson plan
Left corner
In formal language theory, the left corner of a production rule in a context-free grammar is the left-most symbol on the right side of the rule. For example, in the rule A→Xα, X is the left corner. The left corner table associates to a symbol all possible left corners for that symbol, and the left corners of those symbols, etc. Given the grammar :S → VP :S → NP VP :VP → V NP :NP → DET N the left corner table is as follows. Left corners are used to add bottom-up filtering to a top-down parser, or top-down filtering to a bottom-up parser.
Article summary
In formal language theory, the left corner of a production rule in a context-free grammar is the left-most symbol on the right side of the rule. For example, in the rule A→Xα, X is the left corner. The left corner table associates to a symbol all possible left corners for that symbol, and the left corners of those symbols, etc. Given the grammar :S → VP :S → NP VP :VP → V NP :NP → DET N the left corner table is as follows. Left corners are used to add bottom-up filtering to a top-down parser, or top-down filtering to a bottom-up parser.
Key claims
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Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
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Key claims and bibliography are generated from the same tracked claims and sources as the article page.