proposition: Lemma NirrS2 : Nirr 'SG_2 = 2.
proof: Proof. Proof using. by rewrite NirrSn card_intpartn. Qed.
imports: mathcomp(all_ssreflect) mathcomp(fingroup perm ssralg morphism perm action) mathcomp(zmodp) mathcomp(vector matrix mxalgebra ssrnum algC) mathcomp(mxrepresentation classfun character) permcomp tools partition congr cycles cycletype presentSn