proposition: Lemma Log_inv n x y : 1 < n -> 0 < x -> 0 < y -> Log n x = Log n y -> x = y.
proof: Proof. move=> n1 Hx Hy. rewrite /Log /Rdiv eqR_mul2r; last exact/invR_neq0/eqP/gtR_eqF/ln_pos. apply ln_inv => //; exact: H. Qed.
imports: mathcomp(all_ssreflect ssralg ssrnum) mathcomp(Rstruct) Reals Lra ssrR Reals_ext mathcomp(reals) realType_ext