English
Similarly, f is antitone iff it is antitone on the interval Icc(l, l+a) for any l, under AddConstMapClass assumptions.
Русский
Аналогично: f антимонотонна тогда и только тогда, когда она антимонотонна на интервале Icc(l, l+a).
LaTeX
$$$\text{Antitone}(f) \iff \text{AntitoneOn}(f, Icc(l, l+a)).$$$
Lean4
theorem antitone_iff_Icc [AddCommGroup G] [LinearOrder G] [IsOrderedAddMonoid G] [Archimedean G] [AddCommGroup H]
[PartialOrder H] [IsOrderedAddMonoid H] [AddConstMapClass F G H a b] {f : F} (ha : 0 < a) (l : G) :
Antitone f ↔ AntitoneOn f (Icc l (l + a)) :=
monotone_iff_Icc (H := Hᵒᵈ) ha l