proposition: Lemma nbhs_subspace_singleton (p : subspace A) B : nbhs p B -> B p.
proof: Proof. by case: nbhs_subspaceP => ? => [/nbhs_singleton|]; apply. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed