DOUBT

Question

what are non inheritably unambiguous and ambiguous grammars

and what are  inheritably unambiguous and ambiguous  grammars

please explain this..

Comments

ok ,but then what is approach to find whether it is inherently ambiguous or not??

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Try to convert the given ambiguous grammar to unambiguous form and if you are sure enough that there is no possible way to make it ambiguity-free then that is inherently ambiguous. 

To make ambiguous to unambiguous watch https://www.youtube.com/watch?v=9vmhcBpZDcE&t=935s

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ohk so  by seeing precedence ,associativity  we can determine whether it is ambiguous or not??

Answer 1

IUL->If there exist unambiguos CFG for any language then it is IUL.

Ex-{a^mbⁿ| m=2n or n=2m}

IAL->Every CFG equivalent to IAL 'L' must be Ambiguos CFG.(No unambiguos CFG exist for IAL)

Ex-{a^mbⁿc^k |m=n or n=k}

 

 

 

 

 

 

 

Set of DCFL's ⊆ Set of IUL's ⊆ Set of CFL's(IAL's)

Every CFG is ambiguos.

Every DCFL,Finite,Regular language is IUL.

Comments

but regular Languages can be ambiguous because of the NFA.

So not every RL unambiguous

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If the grammar derives a  string in more than one way Then it is Ambiguos..

Anyway NFA can be converted to it's equivalent DFA.

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ohk means regular can be ambiguous but cannot be inherently ambiguous

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Yes..

Refer to this:

https://gateoverflow.in/10736/inherently-ambiguous-grammar