Re: Hom(Z x Z, Z) - is it a cyclic group



On Jan 22, 12:06 pm, Christopher Kolago <precar...@xxxxxxxx> wrote:
Is a group of all homomorphisms from (Z x Z) to Z cyclic or is it not? As far as I can remember it's not cyclic (I solved this problem about a year ago, but today I'm somehow unable to prove it; bad day, I think...)

Take the two projection maps p_1, p_2 : Z x Z --> Z. It is
clearly false that either p_1 is a multiple of p_2 or
p_2 is a multiple of p_1.

-- m
.