Hi,

I've just wanted to clear it up: Suppose we do prove claim (a) for the RE class, and then prove that for every infinite language L in general the claim in (a) is not true.

Isn't (b) a little bit stronger then (a)? If we prove that (a) is not true for any language L, then it is not true for a language L in RE…?

Can someone settle this…? where did I get it wrong?

Thank you!