(I J : Ideal R) : I ⊆ (I :: J). Proof. intros x i; split; apply tr; intros r j; cbn. - by rapply isrightideal. - by rapply isleftideal. Defined.
Require Import Basics Types. Require Import Spaces.Finite.Fin. Require Import Classes.interfaces.canonical_names. Require Import Algebra.Rings.Ring. Require Import Algebra.Groups.Subgroup. Require Import Algebra.AbGroups. Require Import WildCat.Core. Module Import Notation.