English
div2(bit b n) = n for any Bool b and natural n.
Русский
div2(bit(b,n)) = n для любого булева b и натурального n.
LaTeX
$$$$ \forall (b : \mathrm{Bool}) (n : \mathbb{N}), \; \mathrm{div2}(\mathrm{bit}(b,n)) = n. $$$$
Lean4
@[simp, grind =]
theorem div2_bit (b n) : div2 (bit b n) = n := by
rw [bit_val, div2_val, Nat.add_comm, add_mul_div_left, div_eq_of_lt, Nat.zero_add] <;> cases b <;> decide