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Fragmentations with self-similar branching speeds

Published online by Cambridge University Press:  22 November 2021

Jean-Jil Duchamps*
Affiliation:
Université Bourgogne Franche-Comté

Abstract

We consider fragmentation processes with values in the space of marked partitions of $\mathbb{N}$, i.e. partitions where each block is decorated with a nonnegative real number. Assuming that the marks on distinct blocks evolve as independent positive self-similar Markov processes and determine the speed at which their blocks fragment, we get a natural generalization of the self-similar fragmentations of Bertoin (Ann. Inst. H. Poincaré Prob. Statist.38, 2002). Our main result is the characterization of these generalized fragmentation processes: a Lévy–Khinchin representation is obtained, using techniques from positive self-similar Markov processes and from classical fragmentation processes. We then give sufficient conditions for their absorption in finite time to a frozen state, and for the genealogical tree of the process to have finite total length.

Type
Original Article
Copyright
© The Author(s) 2021. Published by Cambridge University Press on behalf of Applied Probability Trust

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Footnotes

*

Postal address: Laboratoire de mathématiques de Besançon, UMR 6623, CNRS, Université Bourgogne Franche-Comté, 16 route de Gray, 25030 Besançon CEDEX, France.

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