English
If hf: UniformConcaveOn s φ f, then UniformConvexOn s φ (-f).
Русский
Если hf: UniformConcaveOn s φ f, то UniformConvexOn s φ (-f).
LaTeX
$$$$ \text{UniformConcaveOn}(s,\phi,f) \Rightarrow \text{UniformConvexOn}(s,\phi,-f). $$$$
Lean4
theorem neg (hf : UniformConcaveOn s φ f) : UniformConvexOn s φ (-f) :=
by
refine ⟨hf.1, fun x hx y hy a b ha hb hab ↦ le_of_neg_le_neg ?_⟩
simpa [add_comm, -neg_le_neg_iff, ← le_sub_iff_add_le', sub_eq_add_neg, neg_add] using hf.2 hx hy ha hb hab