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 ].
Prove the following:
(a) Let A be a ring and B be a field. Let f : A → B be a
surjective homomorphism from A to B. Then ker(f) is a maximal
ideal.
(b) If A/J is a field, then J is a maximal ideal.
If F is a field and ?(?),?(?),h(?) ∈ ?[?]; and
h(?) ≠ 0.
a) Prove that [?(?)] = [?(?)] if and only if ?(?) ≡ ?(?)(???(
(h(?)).
b) Prove that congruence classes modulo h(?) are either disjoint
or identical.
A
theorem for you to prove: Let B be a local ring containing a
perfect field k that is isomorphic to its residue field B/m, and
such that B is a localization of a finitely generated k-algebra.
Then the module of relative differential forms M_B/k is a free
B-module of rank equal to the dimension of B if and only if B is a
regular local ring.