We discuss the factorization problem on topological groups. We focus on the topological aspect of the problem and give a necessary condition for a topological group G to be the the semidirect product of two closed subgroups. Also, we show that if G = K o H, then the integral of a measurable function on G can be obtained by calculating an iterated integral on K and H. Moreover, G=H has a relatively invariant Radon measure  and Lp(G=H) is isometrically isomorphic to Lp(K) when G=H is attached to .

Keywords