You are given the following information about formal languages L, L2, L3, L4, and L5, all...

 

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You are given the following information about formal languages L₁, L2, L3, L4, and L5, all defined over alphabet = {a,b}: A regular grammar can generate all strings in L₁ and nothing else. A deterministic top-down parser can be built for context-free grammar whose language is L2. • Only an inherently ambiguous context-free grammar can be provided for L3. • There is a TM M that decides LA L(a*b*). • An unrestricted grammar can generate all strings in L5. Let L = (L₂L1L5)* U (LL4). a. Show precisely how to accept a string in L by using abstract machines constructed for L₁, L2, L3, L4, and L5. b. Can we always come up with a TM that semidecides L? Justify your answer. You are given the following information about formal languages L₁, L2, L3, L4, and L5, all defined over alphabet = {a,b}: A regular grammar can generate all strings in L₁ and nothing else. A deterministic top-down parser can be built for context-free grammar whose language is L2. • Only an inherently ambiguous context-free grammar can be provided for L3. • There is a TM M that decides LA L(a*b*). • An unrestricted grammar can generate all strings in L5. Let L = (L₂L1L5)* U (LL4). a. Show precisely how to accept a string in L by using abstract machines constructed for L₁, L2, L3, L4, and L5. b. Can we always come up with a TM that semidecides L? Justify your answer.

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a To accept a string in L we can use the abstract machines constructed for L1 L2 L3 L4 and L5 as follows 1 L1 Since L1 is defined by a regular grammar ... View the full answer