I am reading the basic concepts of the Green-Tao theorem (and also reading the previous questions at MSE about the corollaries of the theorem). According to the Wikipedia, the theorem can be stated as: "there exist arithmetic progressions of primes, with $k$ terms, where $k$ can be any natural number". There is also an extension of the result to cover polynomial progressions.
My question is very basic, but I am not sure about the answer of this:
If green-Tao theorem is true for prime numbers, then would it be true automatically for those numbers whose Möbius function value is $\mu(n)=-1$?
Something like (1):"there exist arithmetic progressions of numbers whose Möbius function value $\mu(n)=-1$, with $k$ terms, where $k$ can be any natural number"
My guess is that if all prime numbers are $\mu(p)=-1$ then the theorem is also true for those numbers whose $\mu(n)=-1$ (including primes and other numbers).
At least if the prime numbers are included (1), then I suppose that is (trivially?) true, but I am not sure if it could be said (2) that the theorem would be true for non-prime numbers whose $\mu(n)=-1$ only (something like: "it is possible to find any kind of arithmetic progression of non-primes whose $\mu(n)=-1$" ).
I guess that (1) could be correct, but (2) would be wrong. Is that right?