proposition: Lemma LogM n x y : 0 < x -> 0 < y -> Log n (x * y) = Log n x + Log n y.
proof: Proof. move=> *; by rewrite /Log -mulRDl ln_mult. Qed.
imports: mathcomp(all_ssreflect ssralg ssrnum) mathcomp(Rstruct) Reals Lra ssrR Reals_ext mathcomp(reals) realType_ext