rw [size_eq]
round : ℕ → ℕ
n a b : ℕ
npos : 0 < n
hfaithful₁ : faithful₁ n round
hfa : trunc n a = a
hfb : trunc n b = b
hba : b ≤ a
no_carry : a + b < 2 ^ Nat.size a
round_le : round (a + b) ≤ a + b
size_eq : Nat.size (a + b) = Nat.size a
⊢ 2 ^ (Nat.size (a + b) - n) = 2 ^ (Nat.size a - n)
no goals