no goals
G : Type u_1
H : Type ?u.237333
α : Type u_2
β : Type ?u.237339
E : Type ?u.237342
inst✝¹⁰ : Group G
inst✝⁹ : Group H
inst✝⁸ : MulAction G α
inst✝⁷ : MeasurableSpace α
inst✝⁶ : MulAction H β
inst✝⁵ : MeasurableSpace β
inst✝⁴ : NormedAddCommGroup E
s t✝ : Set α
μ : Measure α
inst✝³ : MeasurableSpace G
inst✝² : MeasurableSMul G α
inst✝¹ : SMulInvariantMeasure G α μ
inst✝ : Countable G
ν : Measure α
h : IsFundamentalDomain G s
t : Set α
⊢ ↑↑μ t = ∑' (g : G), ↑↑μ (g • t ∩ s)
simpa only [set_lintegral_one] using h.set_lintegral_eq_tsum' (fun _ => 1) t