proposition: Lemma injm_pairg1 : 'injm pairg1.
proof: Proof. by apply/subsetP=> x /morphpreP[_ /set1P[->]]; apply: set11. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq div) mathcomp(choice fintype bigop finset fingroup morphism) mathcomp(quotient action)