English
If s is a set and f_i are AEMeasurable, then the a.e. measurable supremum over i∈s is AEMeasurable.
Русский
Если f_i — AEMеас measurable, то на множесто s верхняя граница по i — AEMеас measurable.
LaTeX
$$theorem AEMeasurable.biSup {ι} {μ : Measure δ} (s : Set ι) {f : ι → δ → α} (hs : s.Countable) (hf : ∀ i ∈ s, AEMeasurable (f i) μ) : AEMeasurable (fun b => ⨆ i ∈ s, f i b) μ$$
Lean4
theorem biInf {ι} {μ : Measure δ} (s : Set ι) {f : ι → δ → α} (hs : s.Countable) (hf : ∀ i ∈ s, AEMeasurable (f i) μ) :
AEMeasurable (fun b => ⨅ i ∈ s, f i b) μ :=
.biSup (α := αᵒᵈ) s hs hf