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On suprema of Lévy processes and application in risk theory

Renming Song, Zoran Vondraček (2008)

Annales de l'I.H.P. Probabilités et statistiques

Let X̂=C−Y where Y is a general one-dimensional Lévy process and C an independent subordinator. Consider the times when a new supremum of X̂ is reached by a jump of the subordinator C. We give a necessary and sufficient condition in order for such times to be discrete. When this is the case and X̂ drifts to −∞, we decompose the absolute supremum of X̂ at these times, and derive a Pollaczek–Hinchin-type formula for the distribution function of the supremum.

On Talagrand's Admissible Net Approach to Majorizing Measures and Boundedness of Stochastic Processes

Witold Bednorz (2008)

Bulletin of the Polish Academy of Sciences. Mathematics

We show that the main result of [1] on sufficiency of existence of a majorizing measure for boundedness of a stochastic process can be naturally split in two theorems, each of independent interest. The first is that the existence of a majorizing measure is sufficient for the existence of a sequence of admissible nets (as recently introduced by Talagrand [5]), and the second that the existence of a sequence of admissible nets is sufficient for sample boundedness of a stochastic process with bounded...

On the local time of sub-fractional Brownian motion

Ibrahima Mendy (2010)

Annales mathématiques Blaise Pascal

S H = { S t H , t 0 } be a sub-fractional Brownian motion with H ( 0 , 1 ) . We establish the existence, the joint continuity and the Hölder regularity of the local time L H of S H . We will also give Chung’s form of the law of iterated logarithm for S H . This results are obtained with the decomposition of the sub-fractional Brownian motion into the sum of fractional Brownian motion plus a stochastic process with absolutely continuous trajectories. This decomposition is given by Ruiz de Chavez and Tudor [10].

Pénalisations de l’araignée brownienne

Joseph Najnudel (2007)

Annales de l’institut Fourier

Dans cet article, nous pénalisons la loi d’une araignée brownienne ( A t ) t 0 prenant ses valeurs dans un ensemble fini E de demi-droites concourantes, avec un poids égal à 1 Z t exp ( α N t X t + γ L t ) , où t est un réel positif, ( α k ) k E une famille de réels indexés par E , γ un paramètre réel, X t la distance de A t à l’origine, N t ( E ) la demi-droite sur laquelle se trouve A t , L t le temps local de ( X s ) 0 s t à l’origine, et Z t la constante de normalisation. Nous montrons que la famille des mesures de probabilité obtenue par ces pénalisations converge vers...

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