∀ {𝕜 : Type u_1} {E : Type u_2} {F : Type u_3} [inst : RCLike 𝕜] [inst_1 : NormedAddCommGroup E]
  [inst_2 : InnerProductSpace 𝕜 E] [inst_3 : NormedAddCommGroup F] [inst_4 : InnerProductSpace 𝕜 F]
  (g : Submodule 𝕜 (E × F)),
  g.adjoint =
    Submodule.map (↑(WithLp.linearEquiv 2 𝕜 (F × E)))
      (Submodule.map (↑((LinearEquiv.skewSwap 𝕜 F E).symm.trans (WithLp.linearEquiv 2 𝕜 (F × E)).symm)) g)ᗮ