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Conférences

le (1h1m15s)

On the modified Palm version (workshop ERC Nemo Processus ponctuels et graphes aléatoires unimodulaires)

The Palm version of a stationary random measure is an important tool in probability. It is however not well known that there are in fact two Palm versions, with related but different interpretations. For lack of better terms, call the well known version standard and the less known version modified. In this talk we shall focus on the modified Palm version and its interpretation. The concepts of shift-coupling and mass-stationarity will play a key role
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Conférences

le (55m56s)

A notion of entropy for limits of sparse marked graphs (workshop ERC Nemo Processus ponctuels et graphes aléatoires unimodulaires)

Bordenave and Caputo (2014) defined a notion of entropy for probability distributions on rooted graphs with finite expected degree at the root. When such a probability distribution \rho has finite BC entropy \Sigma(\rho), the growth in the number of vertices n of the number of graphs on n vertices whose associated rooted graph distribution is close to \rho is as d/2 n \log n + \Sigma(\rho) n + o(n), where d is expected degree of the root under \rho. We develop the parallel result for probability distributions on marked rooted graphs. Our graphs have vertex marks drawn from a finite ...
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Conférences

le (59m49s)

Sampling cluster point processes: a review (workshop ERC Nemo Processus ponctuels et graphes aléatoires unimodulaires)

The theme of this talk is the sampling of cluster and iterated cluster point processes. It is partially a review, mainly of the Brix–Kendall exact sampling method for cluster point processes and its adaptation by Moller and Rasmussen to Hawkes branching point processes on the real line with light-tail fertility rate. A formal proof via Laplace transforms of the validity of the method in terms of general clusters that are not necessarily point processes fits this purpose and allows to include the exact sampling of Boolean ...
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Conférences

le (52m52s)

Absence of percolation for Poisson outdegree-one graphs (workshop ERC Nemo Processus ponctuels et graphes aléatoires unimodulaires)

A Poisson outdegree-one graph is a directed graph based on a marked Poisson point process such that each vertex has only one outgoing edge. We state the absence of percolation for such graphs satisfying two assumptions. The Shield assumption roughly says that the graph is locally determined with possible random horizons. The Loop assumption ensures that any forward branch merges on a loop provided that the Poisson point process is augmented with a finite collection of well-chosen points. This result allows to solve a ...
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Conférences

le (53m51s)

Subdiffusivity of random walks on random planar maps, via stationarity (workshop ERC Nemo Processus ponctuels et graphes aléatoires unimodulaires)

Random planar maps have been the subject of numerous studies over the last years. They are instance of stationary and reversible random planar maps exhibiting a non-conventional geometry at large scale. Because of their “fractal” geometry, the simple random walk on these random graphs is believed to be subdiffusive, i.e. it displaces slowler than in the regular grid case. We will propose an approach to such results strongly based on the stationary of these random graphs, i.e. the fact that their distributions is invariant under ...
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Conférences

le (42m40s)

Stein-Malliavin method for discrete alpha stable point processes (workshop ERC Nemo Processus ponctuels et graphes aléatoires unimodulaires)

The notion of discrete alpha-stable point processes generalizes to point processes the notion of stable distribution. It has been introduced and studied by Davydov, Molchanov and Zuyev a few years ago. Their stability property leaves a large degree of variability in the choice of their driving characteristics but enforces a rich mathematical structure. We show how to build a Dirichlet-Malliavin structure for these processes and we apply this framework to several limit theorems. Some known results for Poisson point processes appear as corollaries of ...
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Conférences

le (46m11s)

Central Limit theorem for quasi-local statistics of point processes with fast decay of correlations (workshop ERC Nemo Processus ponctuels et graphes aléatoires unimodulaires)

We shall consider Euclidean stationary point processes which have fast decay of correlations i.e., their correlation functions factorize upto an additive error decaying exponentially in the separation distance. By a quasi-local statistic of the point process, we refer to statistics that can be expressed as sum of contributions from the points and the contribution of every point being determined by a random ball around the point whose radius has an exponential tail. There are many well-known point processes and statistics that satisfy these conditions ...
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Conférences

le (56m5s)

Eternal family trees and dynamics on unimodular random graphs (workshop ERC Nemo Processus ponctuels et graphes aléatoires unimodulaires)

This talk is centered on covariant dynamics on unimodular random graphs and random networks (marked graphs), namely maps from the set of vertices to itself which are preserved by graph or network isomorphisms. Such dynamics are referred to as vertex-shifts here. These dynamics have point-shifts on point processes as a subclass. First we give a classification of vertex-shifts on unimodular random networks. Each such vertex-shift partitions the vertices into a collection of connected components and foils. The latter are discrete analogues the stable manifold ...
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