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The speed of propagation for KPP type problems. I: Periodic framework

Henry Berestycki, François Hamel, Nikolai Nadirashvili (2005)

Journal of the European Mathematical Society

This paper is devoted to some nonlinear propagation phenomena in periodic and more general domains, for reaction-diffusion equations with Kolmogorov–Petrovsky–Piskunov (KPP) type nonlinearities. The case of periodic domains with periodic underlying excitable media is a follow-up of the article [7]. It is proved that the minimal speed of pulsating fronts is given by a variational formula involving linear eigenvalue problems. Some consequences concerning the influence of the geometry of the domain,...

The well-posedness of a swimming model in the 3-D incompressible fluid governed by the nonstationary Stokes equation

Alexander Khapalov (2013)

International Journal of Applied Mathematics and Computer Science

We introduce and investigate the well-posedness of a model describing the self-propelled motion of a small abstract swimmer in the 3-D incompressible fluid governed by the nonstationary Stokes equation, typically associated with low Reynolds numbers. It is assumed that the swimmer's body consists of finitely many subsequently connected parts, identified with the fluid they occupy, linked by rotational and elastic Hooke forces. Models like this are of interest in biological and engineering applications...

Topological properties of the solution set of a class of nonlinear evolutions inclusions

Nikolaos S. Papageorgiou (1997)

Czechoslovak Mathematical Journal

In the paper we study the topological structure of the solution set of a class of nonlinear evolution inclusions. First we show that it is nonempty and compact in certain function spaces and that it depends in an upper semicontinuous way on the initial condition. Then by strengthening the hypothesis on the orientor field F ( t , x ) , we are able to show that the solution set is in fact an R δ -set. Finally some applications to infinite dimensional control systems are also presented.

Traces and the F. and M. Riesz theorem for vector fields

Shiferaw Berhanu, Jorge Hounie (2003)

Annales de l’institut Fourier

This work studies conditions that insure the existence of weak boundary values for solutions of a complex, planar, smooth vector field L . Applications to the F. and M. Riesz property for vector fields are discussed.

Un résultat générique d’unicité pour les équations d’évolution

Laure Saint-Raymond (2002)

Bulletin de la Société Mathématique de France

Soit un espace topologique, ' un espace métrique et ( S ) un système d’équations d’évolution admettant une solution dans  ' pour toute donnée initiale dans  et stable vis-à-vis des données initiales sur . On montre que l’ensemble des données initiales pour lesquelles ( S ) admet une unique solution est un G δ de . En particulier, si l’unicité est vraie sur un sous-ensemble dense de , elle l’est génériquement.

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