English
If f and g are strictly concave on s, then their pointwise minimum h(x) = min{f(x), g(x)} is strictly concave on s.
Русский
Если f и g строго увкальны на s, то их точечный минимум h(x) = min{f(x), g(x)} строго увкля на s.
LaTeX
$$$\StrictConcaveOn(\mathfrak{K}, s, f) \land \StrictConcaveOn(\mathfrak{K}, s, g) \Rightarrow \StrictConcaveOn(\mathfrak{K}, s, x \mapsto \min\{f(x), g(x)\})$$$
Lean4
/-- The pointwise minimum of strictly concave functions is strictly concave. -/
theorem inf (hf : StrictConcaveOn 𝕜 s f) (hg : StrictConcaveOn 𝕜 s g) : StrictConcaveOn 𝕜 s (f ⊓ g) :=
hf.dual.sup hg