# Questions tagged [ambiguity]

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### Why are ambiguous grammars bad?

I understand that if there exist 2 or more left or right derivation trees, then the grammar is ambiguous, but I am unable to understand why it is so bad that everyone wants to get rid of it.
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### Explanation of Grammar Ambiguity

Consider now the grammar G S -> (S + S) S -> (S * S) S -> a Is it ambiguous? Answer: No because there are disambiguating parentheses and so no left or right recursion. Can someone explain how the ...
579 views

### Is this unambiguous grammar equivalent?

I have a simple context free grammar $(\{A\}, \{(,)\}, R, A)$, which consists of this one production rule: $A \rightarrow AA\, \vert\, (A)\, \vert\, \epsilon$ I believe this is ambiguous! For ...
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### Context-free grammars and priority

This grammar is supposed to give priority to multiplication: E -> E + T | T. T -> T * F | F. F -> x. A derivation for "x + x * x" would be (unless I'm wrong): E => E + T => T + T => F + T => x + T =...
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### Finding an unambiguous grammar of a language provided by a CFG

I'm working through 'Intro to Automata Theory, Language and Computation' 2nd edition by Hopcroft, Motwani & Ullman. In section 5.4, exercise 5.4.3 I am tasked with finding an unambiguous grammar ...
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### Equivalent unambiguous grammar

Given the grammar: $S \to AS\mid \varepsilon$ $A \to A1\mid 0A1 \mid \varepsilon$ Generate a new unambiguous grammar that generates the same language as the grammar above. I have no idea how to ...
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### unambiguous equivalent grammar

There is a grammar G given: S->XaX X->aX|bX|eps I just replied to the first question that was ...
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### Find unambiguous grammar for an ambiguous grammar

Hi I want to find an unambiguous grammar for a known ambiguous one, and the production is like this: S->bA|aB A->a|aS|bAA B->b|bS|aBB I have found the ...
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### How to decide if CSP is ambiguous?

When you pick up some reading about CSP the main focus is how to solve it. My goal is to compute/decide if CSP is ambiguous (has 2 or more solutions) or not (has 1 solution). Of course brute-force ...