I have two questions:

1) In the test, if I want to prove that a language is in NP as a part of

some bigger proof that I want to make (I mean that proving that the

language is in NP is not "the main goal" of the question. in other words,

I ask you about questions like when I want to prove that the language

is in NPC and as a part of it I have to prove it is in NP), how much

(roughly speaking) do I have to write about that?

2) About proving a reduction like A_{TM} <=_{m} L

(from the acception problem to L), I prove that :

(1) if <M,w> is in A_{TM} so f(<M,w>) is in L

(2) if <M,w> is not in A_{TM} (means is in the complement) so f(<M,w>) is not in L

In (2) : How much do I have to say something about the option that the encoding is not proper?

thanks

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