English
If h is MonovaryOn f g on s and g' is AntitoneOn on g(s), then AntivaryOn f (g'∘g) on s.
Русский
Если h = MonovaryOn f g на s и g' антитонична на g(s), то AntivaryOn f (g'∘g) на s.
LaTeX
$$$$ MonovaryOn\\;f\\;g\\;s \\land AntitoneOn\\;g'\\;(g''s) \\Rightarrow AntivaryOn\\;f\\;(g'\\circ g)\\;s $$$$
Lean4
protected theorem monovaryOn (hf : MonotoneOn f s) (hg : MonotoneOn g s) : MonovaryOn f g s := fun _ hi _ hj hij =>
hf hi hj (hg.reflect_lt hi hj hij).le