English
For a function f: Option β → α, the infimum over all options equals the minimum of the value at none and the infimum over all some values: ⨅ o, f o = f none ⊓ ⨅ b, f (Some b).
Русский
Для функции f: Option β → α инфимум по всем Option равен минимуму значения в none и инфимума по всем some b: ⨅ o, f o = f none ⊓ ⨅ b, f (Some b).
LaTeX
$$$\\displaystyle \\big\\wedge_{o} f(o) = f(\\text{none}) \\;\\sqcap\\; \\big\\wedge_{b} f(\\text{Some } b)$$$
Lean4
theorem iInf_option (f : Option β → α) : ⨅ o, f o = f none ⊓ ⨅ b, f (Option.some b) :=
@iSup_option αᵒᵈ _ _ _