CODEWITHSUNDEEP
context-free-grammarlanguage-theoryregular-language
confused
confused

Reputation: 31

How do you classify languages into regular, context free, and phrase-structure?

If you're given a language, how do you figure out if it's regular, CF but not regular, or phrase-structure but not CF? Is there a good way to attack this problem? I could randomly try to make FAs or PDAs, but I feel like there's a better way to do it.

Classic example:

L = { a^n b^n c^n | n >= 0 }

Where would one start? Thanks.

Upvotes: 3

Views: 500

Answers (1)

WhirlWind
WhirlWind

Reputation: 14112

You sort of get a feel for classifying them. I don't know of a very methodical approach. Since languages are usually subsets and supersets of each other, you estimate where it fits in that hierarchy and show that it can't be, say, a regular language, but it could be a CFL.

Upvotes: 1

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