Exponential transforms of finite disjoint measurable partitions inside finite-rate boxes.
See Bertoin, Lévy Processes, Chapter IV.
theorem
BGW.StableTrees.excursion_laplace_partition
{ι : Type u_1}
[Fintype ι]
{θ : ℝ}
(hθ : 1 < θ ∧ θ ≤ 2)
{ξ : Skorokhod.DLoc → MeasureTheory.Measure (NNReal × Excursion)}
(hξ : Measurable ξ)
(hae : ξ =ᵐ[↑(stableLocalLaw θ)] excursionPointMeasure)
(T ε : NNReal)
(hε : 0 < ε)
(B : ι → Set (NNReal × Excursion))
(hB : ∀ (i : ι), MeasurableSet (B i))
(hsub : ∀ (i : ι), B i ⊆ Set.Ioc 0 T ×ˢ {e : Excursion | ε < e.lifetime})
(hd : Pairwise (Function.onFun Disjoint B))
(c : ι → ENNReal)
:
∫⁻ (f : Skorokhod.DLoc), expNeg (∑ i : ι, c i * (ξ f) (B i)) ∂↑(stableLocalLaw θ) = expNeg (∑ i : ι, (1 - expNeg (c i)) * (lebNN.prod (excursionMeasure θ)) (B i))
Finite disjoint measurable partitions in a lifetime-slab box have the Poisson exponential transform, including infinite coefficients.