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Potentials of a Markov process are expected suprema

Published online by Cambridge University Press:  01 March 2007

Hans Föllmer
Affiliation:
Humboldt-Universität zu Berlin, Institut für Mathematik, Unter den Linden 6, 10099 Berlin, Germany; foellmer@math.hu-berlin.de; knispel@math.hu-berlin.de
Thomas Knispel
Affiliation:
Humboldt-Universität zu Berlin, Institut für Mathematik, Unter den Linden 6, 10099 Berlin, Germany; foellmer@math.hu-berlin.de; knispel@math.hu-berlin.de
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Abstract

Expected suprema of a function f observed along the paths of a nice Markov process define an excessive function, and in fact a potential if f vanishes at the boundary. Conversely, we show under mild regularity conditions that any potential admits a representation in terms of expected suprema. Moreover, we identify the maximal and the minimal representing function in terms of probabilistic potential theory. Our results are motivated by the work of El Karoui and Meziou (2006) on the max-plus decomposition of supermartingales, and they provide a singular analogue to the non-linear Riesz representation in El Karoui and Föllmer (2005).

Type
Research Article
Copyright
© EDP Sciences, SMAI, 2007

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References

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