proposition: Lemma section_reprP s : section_repr s \isog s.
proof: Proof. by rewrite /section_repr; case: pickP => //= /(_ s); rewrite isog_refl. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(choice fintype bigop finset fingroup morphism) mathcomp(automorphism quotient action gseries)