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9 matches found
III: 06, 115-136, LNM 88 (1969)
DELLACHERIE, Claude
Ensembles aléatoires II (Descriptive set theory, Markov processes)
Among the many proofs that an uncountable Borel set of the line contains a perfect set, a proof of Sierpinski (Fund. Math., 5, 1924) can be extended to an abstract set-up to show that a non-semi-polar Borel set contains a non-semi-polar compact set
Comment: See Dellacherie, Capacités et Processus Stochastiques, Springer 1972. More recent proofs no longer depend on rabotages'': Dellacherie-Meyer, Probabilités et potentiel, Appendix to Chapter IV
Keywords: Sierpinski's rabotages'', Semi-polar sets
Nature: Original
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IV: 06, 71-72, LNM 124 (1970)
DELLACHERIE, Claude
Au sujet des sauts d'un processus de Hunt (Markov processes)
Two a.s. results on jumps: the process cannot jump from a semi-polar set; at the first hitting time of any finely closed set $F$, either the process does not jump, or it jumps from outside $F$
Comment: Both results are improvements of previous results of Meyer and Weil
Keywords: Hunt processes, Semi-polar sets
Nature: Original
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V: 06, 76-76, LNM 191 (1971)
CHUNG, Kai Lai
A simple proof of Doob's convergence theorem (Potential theory)
Doob's theorem is a version of the main convergence theorem of potential theory: the limit of a decreasing sequence of excessive functions differs of its regularized version on a semi-polar set
Comment: It is also shown that a function $f$ satisfying $f\ge P_Kf$ for all compact sets $K$ differs from its regularized function on a semi-polar set
Keywords: Excessive functions, Semi-polar sets
Nature: New exposition of known results
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V: 26, 275-277, LNM 191 (1971)
REVUZ, Daniel
Remarque sur les potentiels de mesure (Markov processes, Potential theory)
The standard proof of the equivalence between semi-polar sets being polar and a very precise domination principle (Blumenthal-Getoor, Markov Processes and Potential Theory, 1968) uses the assumption that excessive functions are lower semicontinuous. This assumption is weakened
Keywords: Polar sets, Semi-polar sets, Excessive functions
Nature: Original
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VII: 07, 51-57, LNM 321 (1973)
DELLACHERIE, Claude
Une conjecture sur les ensembles semi-polaires (Markov processes)
For a right process satisfying the absolute continuity hypothesis and assuming singletons are semi-polar sets, it is conjectured that a (nearly-)Borel set is semipolar if and only if it does not contain uncountable families of disjoint, non-polar compact sets. This statement implies that two processes which have the same polar sets also have the same semi-polar sets
Comment: The conjecture can be proved, using a general result of Mokobodzki, see 1238
Keywords: Polar sets, Semi-polar sets
Nature: Original
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IX: 29, 495-495, LNM 465 (1975)
DELLACHERIE, Claude
Une propriété des ensembles semi-polaires (Markov processes)
It is shown that semi-polar sets are exactly those which have potential 0 for all continuous additive functionals (or for all time-changed processes)
Keywords: Semi-polar sets
Nature: Original
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X: 29, 544-544, LNM 511 (1976)
DELLACHERIE, Claude
Correction à des exposés de 1973/74 (Descriptive set theory)
Corrections to 915 and 918
Keywords: Analytic sets, Semi-polar sets, Suslin spaces
Nature: Original
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XII: 38, 509-511, LNM 649 (1978)
DELLACHERIE, Claude
Appendice à l'exposé de Mokobodzki (Measure theory, General theory of processes)
Some comments on 1237: a historical remark, a relation with a result of Talagrand, the inclusion of a converse (due to Horowitz) to the case of finite sections, and the solution to the conjecture from 707
Keywords: Sets with countable sections, Semi-polar sets
Nature: Original
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XII: 43, 564-566, LNM 649 (1978)
DELLACHERIE, Claude; MOKOBODZKI, Gabriel
Deux propriétés des ensembles minces (abstraits) (Descriptive set theory)
Given a class ${\cal S}$ of Borel sets understood as small'' sets, the class ${\cal L}$ consisting of their conplements understood as large'' sets, a set $A$ is said to be ${\cal S}$-thin if does not contain uncountably many disjoint large'' sets. For instance, if ${\cal S}$ is the class of polar sets, then thin sets are the same as semi-polar sets. Two general theorems are proved here on thin sets
Keywords: Thin sets, Semi-polar sets, Essential suprema
Nature: Original
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