Abstract:
We consider a Brownian continuum random tree τ and its local time process at level s, say Zs, which evolves as a Feller branching diffusion. Denote by H(τ) and N the height and the law of the tree τ, respectively. Let μ∈R be a constant. We show that under
N[e−μH(τ)(τ,Z)∈⋅|∫∞0Zsds=r]N[e−μH(τ)|∫∞0Zsds=r]d⟶Law[(τμ,Zμ)],in a local sense,
where if μ<0, then τμ is a Kesten tree and
if μ>0,
then τμ is the so-called Poisson tree constructed in Abraham, Delmas and He (2022, arXiv) by studying the local limits of τ. Moreover, Zμ is the local time process of τμ, which is a new
diffusion, as already proved by Overbeck in 1994 by studying the Martin boundary of Z. We give a new representation of this diffusion using an
elementary SDE with a Poisson immigration. The talk is based on some ongoing works with Romain Abraham, Jean-François Delmas and Meltem Ünel.