. exact b₁_hi_of_two_mul_le_of_lt_round npos hfaithful₀ hfaithful₁
    hfa hfb two_mul_lt.le lt_round
case inr.inr.inl.inl.right
round : ℕ → ℕ
n a b : ℕ
npos : 0 < n
hfaithful₀ : faithful₀ n round
hfaithful₁ : faithful₁ n round
hcorrect₀ : correct₀ n round
hfa : trunc n a = a
hfb : trunc n b = b
hba : b ≤ a
no_uflow : a - b ≥ 2 ^ n
bpos : b > 0
two_mul_lt : 2 * b < a
lt_round : a - b < round (a - b)
⊢ trunc n (round (a - b) - (a - b)) = round (a - b) - (a - b)
no goals