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On the age-dependent predator-prey model

Antoni Leon Dawidowicz, Anna Poskrobko, Jerzy Leszek Zalasiński (2011)

Applicationes Mathematicae

The paper deals with the description of a model which is the synthesis of two classical models, the Lotka-Volterra and McKendrick-von Foerster models. The existence and uniqueness of the solution for the new population problem are proved, as well the asymptotic periodicity but under some simplifying assumptions.

On the distribution of free path lengths for the periodic Lorentz gas II

François Golse, Bernt Wennberg (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

Consider the domain Z ϵ = { x n ; d i s t ( x , ϵ n ) > ϵ γ } and let the free path length be defined as τ ϵ ( x , v ) = inf { t > 0 ; x - t v Z ϵ } . In the Boltzmann-Grad scaling corresponding to γ = n n - 1 , it is shown that the limiting distribution φ ϵ of τ ϵ is bounded from below by an expression of the form C/t, for some C> 0. A numerical study seems to indicate that asymptotically for large t, φ ϵ C / t . This is an extension of a previous work [J. Bourgain et al., Comm. Math. Phys.190 (1998) 491-508]. As a consequence, it is proved that the linear Boltzmann type transport equation is inappropriate...

On the interior boundary-value problem for the stationary Povzner equation with hard and soft interactions

Vladislav A. Panferov (2004)

Annali della Scuola Normale Superiore di Pisa - Classe di Scienze

The Povzner equation is a version of the nonlinear Boltzmann equation, in which the collision operator is mollified in the space variable. The existence of stationary solutions in L 1 is established for a class of stationary boundary-value problems in bounded domains with smooth boundaries, without convexity assumptions. The results are obtained for a general type of collision kernels with angular cutoff. Boundary conditions of the diffuse reflection type, as well as the given incoming profile, are...

On the linear force-free fields in bounded and unbounded three-dimensional domains

Tahar-Zamène Boulmezaoud, Yvon Maday, Tahar Amari (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

Linear Force-free (or Beltrami) fields are three-components divergence-free fields solutions of the equation curlB = αB, where α is a real number. Such fields appear in many branches of physics like astrophysics, fluid mechanics, electromagnetics and plasma physics. In this paper, we deal with some related boundary value problems in multiply-connected bounded domains, in half-cylindrical domains and in exterior domains.

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