have : ⟨i+1,h⟩ = l := Fin.eq_of_val_eq hil
n i : Nat
h : i + 1 < n
l : Fin n
hlt : { val := i, isLt := (_ : i < n) } < l
hinv✝ : (transposAdj i h)[↑{ val := i, isLt := (_ : i < n) }] > (transposAdj i h)[↑l]
hinv :
  { val := i + 1, isLt := h } >
    if i + 1 = ↑l then { val := i, isLt := (_ : i < n) }
    else
      { val := ↑l,
        isLt := (_ : (fun x i => i < n) (transpos { val := i, isLt := (_ : i < n) } { val := i + 1, isLt := h }) ↑l) }
hil : i + 1 = ↑l
⊢ { fst := { val := i, isLt := (_ : i < n) }, snd := l, lt := hlt, inverted := hinv✝ } =
    transposInversion { val := i, isLt := (_ : i < n) } { val := i + 1, isLt := h } (_ : i < Nat.succ i)
n i : Nat
h : i + 1 < n
l : Fin n
hlt : { val := i, isLt := (_ : i < n) } < l
hinv✝ : (transposAdj i h)[↑{ val := i, isLt := (_ : i < n) }] > (transposAdj i h)[↑l]
hinv :
  { val := i + 1, isLt := h } >
    if i + 1 = ↑l then { val := i, isLt := (_ : i < n) }
    else
      { val := ↑l,
        isLt := (_ : (fun x i => i < n) (transpos { val := i, isLt := (_ : i < n) } { val := i + 1, isLt := h }) ↑l) }
hil : i + 1 = ↑l
this : { val := i + 1, isLt := h } = l
⊢ { fst := { val := i, isLt := (_ : i < n) }, snd := l, lt := hlt, inverted := hinv✝ } =
    transposInversion { val := i, isLt := (_ : i < n) } { val := i + 1, isLt := h } (_ : i < Nat.succ i)