∀ {M : Type u_10} {N : Type u_11} [inst : Mul M] [inst_1 : Mul N] (toFun : M → N)
  (map_mul' : ∀ (x y : M), toFun (x * y) = toFun x * toFun y) (toFun_1 : M → N)
  (map_mul'_1 : ∀ (x y : M), toFun_1 (x * y) = toFun_1 x * toFun_1 y),
  ({ toFun := toFun, map_mul' := map_mul' } = { toFun := toFun_1, map_mul' := map_mul'_1 }) = (toFun = toFun_1)