proposition: Lemma fdistD1E a : fdistD1 a = if a == b then 0 else X a / (1 - X b).
proof: Proof. by rewrite /fdistD1; unlock; rewrite ffunE. Qed.
imports: mathcomp(all_ssreflect ssralg fingroup perm matrix) mathcomp(all_algebra vector reals normedtype) mathcomp(mathcomp_extra boolp) mathcomp(Rstruct) ssrR logb realType_ext ssr_ext ssralg_ext bigop_ext