{R : Ring} : LeftIdeal R -> LeftIdeal R -> LeftIdeal R := fun I J => Build_LeftIdeal R (subgroup_intersection I J) _.
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.