English
The additive circle AddCircle T carries a natural measure space structure whose total mass is the Haar measure scaled to mass T.
Русский
У кольца AddCircle T есть естественное структурное пространство меры, суммарность которого равна массы Т дляhaar-меры.
LaTeX
$$$\\text{volume} = (\\text{Haar measure on AddCircle}(T))$$$
Lean4
/-- Equip the "additive circle" `ℝ ⧸ (ℤ ∙ T)` with, as a standard measure, the Haar measure of total
mass `T` -/
noncomputable instance measureSpace : MeasureSpace (AddCircle T) :=
{ QuotientAddGroup.measurableSpace _ with volume := ENNReal.ofReal T • addHaarMeasure ⊤ }