English
For a measurable t, the measure equals the average number of occurrences of elements of s in t.
Русский
Для измеримого t мера равна среднему числу вхождений элементов s в t.
LaTeX
$$$$ (\\mathrm{toMeasure\\_ofMultiset\\, apply}\\; s\\; hs).toMeasure\\; t = \\frac{\\sum' x, (s.filter(\\cdot \\in t)).count x}{\\mathrm{Multiset}.card s} $$$$
Lean4
@[to_additive]
theorem hasLaw_fun_mul {M : Type*} [Monoid M] {mM : MeasurableSpace M} [MeasurableMul₂ M] {μ ν : Measure M}
[SigmaFinite μ] [SigmaFinite ν] {X Y : Ω → M} (hX : HasLaw X μ P) (hY : HasLaw Y ν P) (hXY : IndepFun X Y P) :
HasLaw (fun ω ↦ X ω * Y ω) (μ ∗ₘ ν) P :=
hXY.hasLaw_mul hX hY