self_doubt

Question

1) L(M) is recognized by a TM having even number of states.

2) L(M) is infinite.

whether this language are follow non-trivial property ?

Whether this languages are decidable  ?.

Comments

1) L(M) is recognized by a TM having even number of states. decidable (ask about machine not language)

2) L(M) is infinite ( undecidable ,ask not trivial property since all TM need not have infinite language)

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@ Anu007 SIR

1 ONE IS TRIVIAL PROPERTY YES??

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yes abhishek ...

Trivial means you can answer without running machine.

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@anu sir

Second one is NOT RE  so it should be not semidecidable or undecidable??

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abhishek we cannot prove language is infinite since we have to wait for infinite time , hence we cannot say yes .

• if for any machine we can say yes only then semidecidable.
• if can say yes or no then decidable.

Same for finite since complete of it so undecidable proved by sice tyes  =$\varnothing$  , tno = $\Sigma ^{*}$

Here tyes $\subseteq$ tno so not RE hance undecidable.

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@Anu007    L(M) is recognized by a TM having even number of states. decidable   

You have said this , as we come to know about the states in TM through its description.

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