(motive : SetTheory.PGame → SetTheory.PGame → Sort u_2) →
  (x x_1 : SetTheory.PGame) →
    ((α β : Type u_1) →
        (xL : α → SetTheory.PGame) →
          (xR : β → SetTheory.PGame) →
            (α_1 β_1 : Type u_1) →
              (yL : α_1 → SetTheory.PGame) →
                (yR : β_1 → SetTheory.PGame) →
                  motive (SetTheory.PGame.mk α β xL xR) (SetTheory.PGame.mk α_1 β_1 yL yR)) →
      motive x x_1