English
The negation of bit b n distributes over the bit: lnot (bit b n) = bit (not b) (lnot n).
Русский
Логическое отрицание не распределяется над битом: lnot (bit b n) = bit (not b) (lnot n).
LaTeX
$$$$ \operatorname{lnot\_{bit}}(b) : \forall n, \operatorname{lnot}(\operatorname{bit}(b,n)) = \operatorname{bit}(\lnot b)(\operatorname{lnot} n). $$$$
Lean4
@[simp]
theorem lnot_bit (b) : ∀ n, lnot (bit b n) = bit (not b) (lnot n)
| (n : ℕ) => by simp [lnot]
| -[n+1] => by simp [lnot]