n b m : ℕ
hm : m ≠ 0
this : digits (b + 2) m ≠ []
⊢ (b + 2) ^ List.length (digits (b + 2) m) ≤ (b + 2) * m
n b m : ℕ
hm : m ≠ 0
⊢ (b + 2) ^ List.length (digits (b + 2) m) ≤ (b + 2) * m
have : digits (b + 2) m ≠ [] := digits_ne_nil_iff_ne_zero.mpr hm
case h.e'_4.h.e'_6
n b m : ℕ
hm : m ≠ 0
this : digits (b + 2) m ≠ []
⊢ m = ofDigits (b + 2) (digits (b + 2) m)
n b m : ℕ
hm : m ≠ 0
this : digits (b + 2) m ≠ []
⊢ (b + 2) ^ List.length (digits (b + 2) m) ≤ (b + 2) * m
convert @pow_length_le_mul_ofDigits b (digits (b+2) m)
  this (getLast_digit_ne_zero _ hm)
no goals
case h.e'_4.h.e'_6
n b m : ℕ
hm : m ≠ 0
this : digits (b + 2) m ≠ []
⊢ m = ofDigits (b + 2) (digits (b + 2) m)
rw [ofDigits_digits]