. exact Nat.le_add_right _ _
n a b : ℕ
npos : 0 < n
hfa : trunc n a = a
le_ulp : b ≤ ulp n a
size_lt : 2 ^ (Nat.size a - 1) < a
⊢ 2 ^ (Nat.size a - 1) ≤ 2 ^ (Nat.size a - 1) + (ulp n a - b)

n a b : ℕ
npos : 0 < n
hfa : trunc n a = a
le_ulp : b ≤ ulp n a
size_lt : 2 ^ (Nat.size a - 1) < a
⊢ 2 ^ (Nat.size a - 1) + (ulp n a - b) ≤ a - b
n a b : ℕ
npos : 0 < n
hfa : trunc n a = a
le_ulp : b ≤ ulp n a
size_lt : 2 ^ (Nat.size a - 1) < a
⊢ 2 ^ (Nat.size a - 1) + (ulp n a - b) ≤ a - b