English
Let f be an arithmetic function valued in the natural numbers. Then applying the natural-to-arithmetic-function embedding yields the same function; i.e., natToArithmeticFunction f = f.
Русский
Пусть f — арифметическая функция со значениями в натуральных числах. Тогда вложение natToArithmeticFunction f = f.
LaTeX
$$$\\forall f:\\mathrm{ArithmeticFunction}(\\mathbb{N}), \\ operatorname{natToArithmeticFunction}(f) = f$$$
Lean4
@[simp]
theorem natCoe_nat (f : ArithmeticFunction ℕ) : natToArithmeticFunction f = f :=
ext fun _ => cast_id _