have hj' : x.stop ≤ j :=
  trans this.symm (trans hi hij :)
case inl
α : Type u
lt : α → α → Bool
inst✝ : LawfulLTBRel lt
x : Subarray α
stop : Nat
h : Algdata.BinaryHeap.heapSort.Intermed lt x stop
i j : Nat
hij : i < j
hj : j < stop
hrng : x.start < x.stop
hi : x.stop - 1 ≤ i
stop_pos : 0 < x.stop
this : x.stop - 1 + 1 = x.stop
⊢ lt (BinaryHeap.popMax lt x).as[j] (BinaryHeap.popMax lt x).as[i] = false
case inl
α : Type u
lt : α → α → Bool
inst✝ : LawfulLTBRel lt
x : Subarray α
stop : Nat
h : Algdata.BinaryHeap.heapSort.Intermed lt x stop
i j : Nat
hij : i < j
hj : j < stop
hrng : x.start < x.stop
hi : x.stop - 1 ≤ i
stop_pos : 0 < x.stop
this : x.stop - 1 + 1 = x.stop
hj' : x.stop ≤ j
⊢ lt (BinaryHeap.popMax lt x).as[j] (BinaryHeap.popMax lt x).as[i] = false