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

Autores: Henri Berestychi, Nikolai Nadirashvili, François Hamel
Localización: Journal of the European Mathematical Society, ISSN 1435-9855, Vol. 7, Nº 2, 2005, págs. 173-214
Idioma: inglés
DOI: 10.4171/jems/26
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Resumen
- 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 \cite{bh}. 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, of the reaction, advection and diffusion coefficients are given. The last section deals with the notion of asymptotic spreading speed. The main properties of the spreading speed are given. Some of them are based on some new Liouville type results for nonlinear elliptic equations in unbounded domains.