English
If α is a densely ordered, conditionally complete linear order and f is continuous and injective, then f is either strictly monotone or strictly antitone.
Русский
Пусть α — плотно упорядоченный обобщённый линейный порядок, и f непрерывна и инъективна; тогда f либо строго монотонна, либо строго антимоносонична.
LaTeX
$$StrictMono f ∨ StrictAnti f$$
Lean4
/-- A continuous function which tendsto `Filter.atBot` along `Filter.atTop` and to `Filter.atTop`
along `atBot` is surjective. -/
theorem surjective' {f : α → δ} (hf : Continuous f) (h_top : Tendsto f atBot atTop) (h_bot : Tendsto f atTop atBot) :
Function.Surjective f :=
Continuous.surjective (α := αᵒᵈ) hf h_top h_bot