Local Notation "''I[' phi ]" := (inertia phi) : group_scope.Canonical inertia_group H phi := Group (@group_set_inertia H phi).Local Notation "''I[' phi ]" := (inertia_group phi) : Group_scope.

(* Specifications: *)
Proof. by rewrite cfIirrE ?cfConjg_irr ?mem_irr. Qed.
Proof. by move=> i; apply/irr_inj; rewrite !conjg_IirrE cfConjgK. Qed
Proof. by rewrite -{2}[y]invgK; apply: conjg_IirrK.
Proof. by rewrite -!irr_eq1 conjg_IirrE c