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Polynomial bounds in the Ergodic theorem for one-dimensional diffusions and integrability of hitting times

Eva Löcherbach, Dasha Loukianova, Oleg Loukianov (2011)

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

Let X be a one-dimensional positive recurrent diffusion with initial distribution ν and invariant probability μ. Suppose that for some p>1, ∃a∈ℝ such that ∀x∈ℝ, and , where Ta is the hitting time of a. For such a diffusion, we derive non-asymptotic deviation bounds of the form ℙν(|(1/t)∫0tf(Xs) ds−μ(f)|≥ε)≤K(p)(1/tp/2)(1/εp)A(f)p. Here f bounded or bounded and compactly supported and A(f)=‖f‖∞ when f is bounded and A(f)=μ(|f|) when f is bounded and compactly supported. We also give, under...

Polynomial deviation bounds for recurrent Harris processes having general state space

Eva Löcherbach, Dasha Loukianova (2013)

ESAIM: Probability and Statistics

Consider a strong Markov process in continuous time, taking values in some Polish state space. Recently, Douc et al. [Stoc. Proc. Appl. 119, (2009) 897–923] introduced verifiable conditions in terms of a supermartingale property implying an explicit control of modulated moments of hitting times. We show how this control can be translated into a control of polynomial moments of abstract regeneration times which are obtained by using the regeneration method of Nummelin, extended to the time-continuous...

Potential theory of hyperbolic Brownian motion in tube domains

Grzegorz Serafin (2014)

Colloquium Mathematicae

Let X = X(t); t ≥ 0 be the hyperbolic Brownian motion on the real hyperbolic space ℍⁿ = x ∈ ℝⁿ:xₙ > 0. We study the Green function and the Poisson kernel of tube domains of the form D × (0,∞)⊂ ℍⁿ, where D is any Lipschitz domain in n - 1 . We show how to obtain formulas for these functions using analogous objects for the standard Brownian motion in 2 n . We give formulas and uniform estimates for the set D a = x : x ( 0 , a ) . The constants in the estimates depend only on the dimension of the space.

Potential theory of one-dimensional geometric stable processes

Tomasz Grzywny, Michał Ryznar (2012)

Colloquium Mathematicae

The purpose of this paper is to find optimal estimates for the Green function and the Poisson kernel for a half-line and intervals of the geometric stable process with parameter α ∈ (0,2]. This process has an infinitesimal generator of the form - l o g ( 1 + ( - Δ ) α / 2 ) . As an application we prove the global scale invariant Harnack inequality as well as the boundary Harnack principle.

Potentials of a Markov process are expected suprema

Hans Föllmer, Thomas Knispel (2007)

ESAIM: Probability and Statistics

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...

Currently displaying 61 – 80 of 149