proposition: Lemma subalgClosedP (algS : subalgClosed A) : subalg_closed algS.
proof: Proof. split; [ exact: rpred1 | | exact: rpredM ]. by move=> a u v uS vS; apply: rpredD; first exact: rpredZ. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)