Canonical pseries_group : {group gT} := group pseries_group_set.Local Notation ConsPred p := (@Cons nat_pred p%N) (only parsing).Implicit Types (A : {set aT}) (G H : {group aT}).

Lemma pseries_rcons pi pis gT (A : {set gT}) : pseries (rcons pis pi) A = pcore_mod A pi (pseries pis A).