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Réarrangement, inégalités maximales et théorèmes ergodiques fractionnaires

Michel Broise, Yves Déniel, Yves Derriennic (1989)

Annales de l'institut Fourier

Étant donné un semi-flot mesurable ( θ x ) x + d préservant une mesure de probabilité μ sur un espace Ω , nous considérons les moyennes ergodiques t - d + d ϕ ( x / t ) f θ x d x ϕ est un “poids” à support compact sur + d , c’est-à-dire que ϕ vérifie ϕ 0 et ϕ ( x ) d x = 1 . Nous démontrons la convergence p.p. de ces moyennes quand t + si f appartient à l’espace de Lorentz défini par le poids ϕ * qui est le réarrangé décroissant de ϕ . En particulier, pour d = 1 , on obtient la convergence p.p. des moyennes de Césarò d’ordre α

Regularity of the effective diffusivity of random diffusion with respect to anisotropy coefficient

M. Cudna, T. Komorowski (2008)

Studia Mathematica

We show that the effective diffusivity of a random diffusion with a drift is a continuous function of the drift coefficient. In fact, in the case of a homogeneous and isotropic random environment the function is C smooth outside the origin. We provide a one-dimensional example which shows that the diffusivity coefficient need not be differentiable at 0.

Relationship between Extremal and Sum Processes Generated by the same Point Process

Pancheva, E., Mitov, I., Volkovich, Z. (2009)

Serdica Mathematical Journal

2000 Mathematics Subject Classification: Primary 60G51, secondary 60G70, 60F17.We discuss weak limit theorems for a uniformly negligible triangular array (u.n.t.a.) in Z = [0, ∞) × [0, ∞)^d as well as for the associated with it sum and extremal processes on an open subset S . The complement of S turns out to be the explosion area of the limit Poisson point process. In order to prove our criterion for weak convergence of the sum processes we introduce and study sum processes over explosion area....

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