pumping lemma

Definitions

1. 1

   A lemma which states that for a language to be a member of a language class any…

   A lemma which states that for a language to be a member of a language class any sufficiently long string in the language contains a section that can be removed or repeated any number of times with the resulting string remaining in the language, used to determine if a particular language is in a given language class (e.g. not regular).

   • There is a pumping lemma for CFLs similar to the one for regular sets. It can be used in the same way to show that certain sets are not context-free.
   • In the literature one finds many pumping lemmas which describe the ability to repeat (pump) certain words repeatedly in some languages, under different circumstances.
   • String-language hierarchies are usually proven using formalism-specific pumping lemmata.

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