Let phi be a homomorphism of a ring R with unity onto a nonzero ring R'. Let u be a unit in R. Show that phi (u) is a unit in R'.
since u is identiy in R, ur=ru=r for each r in R.
since phi is a homomorphism from R onto R', for each r' in R' there exists r in R such that
Ring Homomorphisms are investigated. The response received a rating of "5" from the student who originally posted the question.