For an arbitrary ring R, prove that a) If I is an ideal of R,
then...
For an arbitrary ring R, prove that a) If I is an ideal of R,
then I[ x] forms an ideal of the polynomial ring R[ x]. b) If R and
R' are isomorphic rings, then R[ x] is isomorphic to R' [ x ].
Let S ⊆ R and let G be an arbitrary isometry of R . Prove that
the symmetry group of G(S) is isomorphic to the symmetry group of
S. Hint: If F is a symmetry of S, what is the corresponding
symmetry of G(S)?
Let R be a commutative ring with identity with the property that
every ideal in R is principal. Prove that every homomorphic image
of R has the same property.