unfold trunc ulp expt
n x : ℕ
npos : 0 < n
round : ℕ → ℕ
hfaithful₀ : faithful₀ n round
hfaithful₁ : faithful₁ n round
hcorrect₁ : correct₁ n round
h : x < trunc n x + ulp n x / 2
uflow : n ≥ Nat.size x
⊢ trunc n x = x
n x : ℕ
npos : 0 < n
round : ℕ → ℕ
hfaithful₀ : faithful₀ n round
hfaithful₁ : faithful₁ n round
hcorrect₁ : correct₁ n round
h : x < trunc n x + ulp n x / 2
uflow : n ≥ Nat.size x
⊢ x / 2 ^ (Nat.size x - n) * 2 ^ (Nat.size x - n) = x