{R : Type} {m n} (M_fun : forall i j, (i < m)%nat -> (j < n)%nat -> R) (i j : nat) (H1 : (i < m)%nat) (H2 : (j < n)%nat) : entry (Build_Matrix R m n M_fun) i j = M_fun i j _ _. Proof. unfold entry. by rewrite 2 entry_Build_Vector. Defined.
Require Import Basics.Overture Basics.Trunc Basics.Tactics Basics.Decidable. Require Import Types.Sigma. Require Import Spaces.List.Core Spaces.List.Theory Spaces.List.Paths. Require Import Algebra.Rings.Ring Algebra.Rings.Module Algebra.Rings.CRing Require Import abstract_algebra. Require Import WildCat.Core WildCat.Paths. Require Import Modalities.ReflectiveSubuniverse.