n✝ m n : ℕ
this : ↑(succAbove (succ 0)) (succ ↑↑0) = succ (↑(succAbove 0) ↑↑0)
⊢ ↑(succAbove 1) 1 = 2
n✝ m n : ℕ
⊢ ↑(succAbove 1) 1 = 2
have := succ_succAbove_succ (0 : Fin (n + 2)) (0 : Fin (n + 2))
n✝ m n : ℕ
this : ↑(succAbove 1) 1 = 2
⊢ ↑(succAbove 1) 1 = 2
n✝ m n : ℕ
this : ↑(succAbove (succ 0)) (succ ↑↑0) = succ (↑(succAbove 0) ↑↑0)
⊢ ↑(succAbove 1) 1 = 2
simp only [succ_zero_eq_one, val_zero, Nat.cast_zero, zero_succAbove, succ_one_eq_two] at this
no goals
n✝ m n : ℕ
this : ↑(succAbove 1) 1 = 2
⊢ ↑(succAbove 1) 1 = 2
exact this