# Language decidable or not?

I have just began with my course of complexity and computability and I need your experience to help me progress !!

Something is not clear for me:

It is asked to determine if L1 is decidable or not, below the language is an answer given by a student. And I'm not agree with it...

The Rice theorem is given as follow :

I don't get why L1 is decidable since, for me, it looks like the Rice theorem could be immediately applied.

Did I understood very badly or am I right ? In the first case, why ?

• @EliaDratwa L1 can not be equal to RE: L1 is a language, RE is a set of languages. The issue here is that $L1 = \{\langle M\rangle\ |\ M \mbox{is a TM}\}$, so to decide L1 we only need to understand whether a word is a description of some TM, which is a simple "parsing" problem, so to speak. – chi Apr 4 at 14:25