Section Norm1vchar.
Variables (gT : finGroupType) (G : {group gT}).
Fact dirr_key : pred_key (dirr G). Proof. by []. Qed.
Canonical dirr_keyed := KeyedPred dirr_key.
Fact dirr_oppr_closed : oppr_closed (dirr G).
Definition dIirr (B : {set gT}) := (bool * (Iirr B))%type.
Definition dirr1 (B : {set gT}) : dIirr B := (false, 0).
Definition ndirr (B : {set gT}) (i : dIirr B) : dIirr B :=
(~~ i.1, i.2).

Lemma dchi_ndirrE (i : dIirr G) : dchi (ndirr i) = - dchi i.