English
If f and g both grow polynomially, then f/g grows polynomially.
Русский
Если обе функции f и g растут полиномиально, то их отношение f/g растёт полиномиально.
LaTeX
$$$\\text{GrowsPolynomially}(f) \\land \\text{GrowsPolynomially}(g) \\Rightarrow \\text{GrowsPolynomially}(x \\mapsto \\tfrac{f(x)}{g(x)})$$$
Lean4
protected theorem div {f g : ℝ → ℝ} (hf : GrowsPolynomially f) (hg : GrowsPolynomially g) :
GrowsPolynomially fun x => f x / g x :=
by
have : (fun x => f x / g x) = fun x => f x * (g x)⁻¹ := by ext; rw [div_eq_mul_inv]
rw [this]
exact GrowsPolynomially.mul hf (GrowsPolynomially.inv hg)