Recent content by samtiro

oh ok. We actually are doing rings before groups so I would not have been able to use groups that is why i resorted to using units. Thanks for confirming my answer!

Homework Statement Explain why Z4 x Z4 is not isomorphic to Z16. Homework Equations Going to talk about units in a ring. Units are properties preserved by isomorphism. The Attempt at a Solution We see the only units in Z4 are 1 and 3. So the units of Z4 x Z4 are (1,1) , (3,3) ...

Homework Statement Let f: R -> S be a homomorphism of Rings and T a subring of S. Let P = { r belongs to R | f(r) belongs to T} Prove P is a subring of R. Homework Equations Theorems used: If S and nonempty subset of R such that S is closed under multiplication and addition, then...