Q1.
(a) Let \mathcalG be a group. Show that \mathcalG is abelian if and only if the map f: \mathcalG × \mathcalG → \mathcalG defined by f(x, y) = x y x-1 y-1 is the trivial map.
(b) Let V be a vector space over \mathbbR and let T: V → V be a linear transformation such that T2 = T. Show that V = ker(T) oplus extIm(T).
(c) Let G be a group and let H be a subgroup of G. Prove that if G is cyclic, then G/H is also cyclic.
(d) Let R be a commutative ring with unity. Show that an ideal I of R is a prime ideal if and only if for any a, b ∈ R, ab ∈ I implies a ∈ I or b ∈ I.
(e) Let F be a field. Show that the set of all polynomials in one variable over F, denoted by F[x], forms a Euclidean domain.