- #1
tom.young84
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"Preimage" of a homomorphism
f:R-->S is a homomorphism of rings and suppose J is an ideal of S.
Prove that f^-1[J]={r in R: f(r) in J} is an ideal of R.
I'm more concerned about how to even start this proof as I am lost.
f:R-->S is a homomorphism of rings and suppose J is an ideal of S.
Prove that f^-1[J]={r in R: f(r) in J} is an ideal of R.
I'm more concerned about how to even start this proof as I am lost.