# Order of Hom(Z,Z/2Z)

I have seen that there exists two group homomorphisms from Z to Z/2Z. However, I cannot seem to understand this. I mean I know that there exists a trivial grp hom. which sends all of Z to 0 in Z/2Z. But I cannot think of anymore. Any help?

Office_Shredder
Staff Emeritus
Gold Member
Well, Z is generated by 1. There are two places 1 can map to, 0 or 1 (mod 2). If it doesn't map to 0, it must map to 1. Do you see what function that really is?

You mean that I map all even to 0 and all odd to 1?

Landau