-variation de fonctions aléatoires. 1ère partie : séries de Rademacher
-variation de fonctions aléatoires. 2ième partie : processus à accroissements indépendants
-variation for families of local times on lines
Parabolic Harnack inequality and estimates of Markov chains on graphs.
On a graph, we give a characterization of a parabolic Harnack inequality and Gaussian estimates for reversible Markov chains by geometric properties (volume regularity and Poincaré inequality).
Parada óptima con horizonte aleatorio.
Analizamos el problema de parada óptima con horizonte aleatorio en procesos de Markov con tiempo continuo. En concreto, estudiamos el caso en el que el horizonte es el tiempo de primera entrada en el interior de un cerrado B. Definimos las funciones B-excesivas y vemos su relación con el pago del problema de parada óptima. Posteriormente introducimos varios conjuntos, que aparecen de forma natural en el problema y que nos permiten caracterizar los dominios de parada. Por último consideramos el caso...
Parametric inference for mixed models defined by stochastic differential equations
Non-linear mixed models defined by stochastic differential equations (SDEs) are considered: the parameters of the diffusion process are random variables and vary among the individuals. A maximum likelihood estimation method based on the Stochastic Approximation EM algorithm, is proposed. This estimation method uses the Euler-Maruyama approximation of the diffusion, achieved using latent auxiliary data introduced to complete the diffusion process between each pair of measurement instants. A tuned...
Parking functions, empirical processes, and the width of rooted labeled trees.
Parrondo's paradox.
Path continuity and last exit distributions
Path transformations of first passage bridges.
Paths of finitely additive brownian motion need not be bizarre
Pathwise differentiability for SDEs in a convex polyhedron with oblique reflection
In this paper, the object of study is a Skorohod SDE in a convex polyhedron with oblique reflection at the boundary. We prove that the solution is pathwise differentiable with respect to its deterministic starting point up to the time when two of the faces are hit simultaneously. The resulting derivatives evolve according to an ordinary differential equation, when the process is in the interior of the polyhedron, and they are projected to the tangent space, when the process hits the boundary, while...
Path-wise solutions of stochastic differential equations driven by Lévy processes.
In this paper we show that a path-wise solution to the following integral equationYt = ∫0t f(Yt) dXt, Y0 = a ∈ Rd,exists under the assumption that Xt is a Lévy process of finite p-variation for some p ≥ 1 and that f is an α-Lipschitz function for some α > p. We examine two types of solution, determined by the solution's behaviour at jump times of the process X, one we call geometric, the other forward. The geometric solution is obtained by adding fictitious time and solving an associated...
Pathwise uniqueness for reflecting Brownian motion in certain planar Lipschitz domains.
Paul Lévy et le mouvement brownien
Ce texte est tiré d’un exposé présenté au cours de la journée Paul Lévy organisée au Laboratoire de Probabilités et Modèles Aléatoires de l’Université Pierre et Marie Curie le 15 décembre 2011. L’objectif de cet exposé était de donner un aperçu des contributions de Paul Lévy à la théorie du mouvement brownien.
PDE's for the Dyson, Airy and Sine processes
In 1962, Dyson showed that the spectrum of a random Hermitian matrix, whose entries (real and imaginary) diffuse according to independent Ornstein-Uhlenbeck processes, evolves as non-colliding Brownian particles held together by a drift term. When , the largest eigenvalue, with time and space properly rescaled, tends to the so-called Airy process, which is a non-markovian continuous stationary process. Similarly the eigenvalues in the bulk, with a different time and space rescaling, tend...
Pedagogic notes on the barrier theorem
Pénalisations de l’araignée brownienne
Dans cet article, nous pénalisons la loi d’une araignée brownienne prenant ses valeurs dans un ensemble fini de demi-droites concourantes, avec un poids égal à , où est un réel positif, une famille de réels indexés par , un paramètre réel, la distance de à l’origine, () la demi-droite sur laquelle se trouve , le temps local de à l’origine, et la constante de normalisation. Nous montrons que la famille des mesures de probabilité obtenue par ces pénalisations converge vers...
Penalisations of multidimensional Brownian motion, VI
As in preceding papers in which we studied the limits of penalized 1-dimensional Wiener measures with certain functionals Γt, we obtain here the existence of the limit, as t → ∞, of d-dimensional Wiener measures penalized by a function of the maximum up to time t of the Brownian winding process (for d = 2), or in {d}≥ 2 dimensions for Brownian motion prevented to exit a cone before time t. Various extensions of these multidimensional penalisations are studied, and the limit laws are described....
Penalization of the Wiener measure and principal values