proposition: Lemma indic_restrict {T : pointedType} {R : numFieldType} (A : set T) : \1_A = (1 : T -> R) \_ A.
proof: Proof. by apply/funext => x; rewrite indicE /patch; case: ifP. Qed.
imports: HB(structures) mathcomp(all_ssreflect ssralg ssrnum ssrint interval finmap) mathcomp(mathcomp_extra boolp classical_sets fsbigop) mathcomp(functions cardinality set_interval) signed reals ereal topology normedtype sequences