{motive : Mathlib.Tactic.ITauto.Proof → Sort u} →
  (t : Mathlib.Tactic.ITauto.Proof) →
    ((t : Mathlib.Tactic.ITauto.Proof) → Mathlib.Tactic.ITauto.Proof.below t → motive t) →
      motive t ×' Mathlib.Tactic.ITauto.Proof.below t