proposition: Lemma cpr_eq_pairAC a b c d : `Pr[ [% TX, TY, TZ] = (a, b, c) | TW = d ] = `Pr[ [% TX, TZ, TY] = (a, c, b) | TW = d ].
proof: Proof. rewrite 2!cpr_eqE; congr (_ / _). rewrite !pr_eqE; congr Pr. apply/setP => u; rewrite !inE /= !xpair_eqE /=; congr (_ && _). by rewrite andbAC. Qed.
imports: mathcomp(all_ssreflect ssralg ssrnum matrix) mathcomp(Rstruct reals) Reals Lra ssrR Reals_ext realType_ext logb ssr_ext ssralg_ext bigop_ext fdist