∀ {R : Type u_1} {n : Type u_2} [inst : NonUnitalNonAssocSemiring R] [inst_1 : Fintype n] [inst_2 : DecidableEq n]
  (c : RingCon (Matrix n n R)), Equivalence fun x y => ∀ (i j : n), c (Matrix.single i j x) (Matrix.single i j y)