∀ {R₁ : Type u_3} {M₁ : Type u_4} [inst : CommRing R₁] [inst_1 : AddCommGroup M₁] [inst_2 : Module R₁ M₁]
  (B : LinearMap.BilinForm R₁ M₁),
  B.IsRefl → ∀ {W : Submodule R₁ M₁}, Disjoint W (B.orthogonal W) → (B.restrict W).Nondegenerate