proposition: Lemma measurable_snd : measurable_fun [set: T1 * T2] snd.
proof: Proof. by have /prod_measurable_funP[] := @measurable_id _ [the measurableType _ of (T1 * T2)%type] setT. Qed.
imports: mathcomp(all_ssreflect all_algebra finmap) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(cardinality fsbigop ) reals ereal signed topology normedtype sequences esum numfun HB(structures)