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Possible Duplicate:
What is a Context Free Grammar?

I can not understand the conceptual meaning of "free" in context free grammar or language? what is free?

Community
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mert inan
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    no definitely not. The question is the meaning of free. if you read the answers on that link, they all explain context free grammar without using "free" word. "free" is only mentined in the name. for example why is not it named as context-dependant grammar? – mert inan Jun 07 '12 at 22:31
  • thanks everyone who voted for duplication! – mert inan Jun 10 '12 at 17:30

1 Answers1

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Context-free is in contrast to context-sensitive. While a context-sensitive grammar has rules of the form

αAβ → αγβ

a context-free one has rules conforming to

A → γ

i.e. A is derivable to γ independent (free) of the context of α and β.

The Wikipedia article on the Chomsky hierarchy explains it in more detail.

Gunther
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