Universal Inherence of Cycle-Free Context-Free Ambiguity Functions
نویسنده
چکیده
It is shown that the set of inherent ambiguity functions for context-free languages and the set of ambiguity functions for cycle-free context-free grammars coincide. Moreover for each census function γ of an unambiguous context-free language the least monotone function larger than or equal to γ is an inherent ambiguity function. Both results are based on a more general theorem. Informally it states that the loss of information induced by a length preserving homomorphism on an unambiguous context-free language can be turned into inherent ambiguity.
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