8 research outputs found

    Pushed traveling fronts in monostable equations with monotone delayed reaction

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    We study the existence and uniqueness of wavefronts to the scalar reaction-diffusion equations ut(t,x)=Δu(t,x)u(t,x)+g(u(th,x)),u_{t}(t,x) = \Delta u(t,x) - u(t,x) + g(u(t-h,x)), with monotone delayed reaction term g:R+R+g: \R_+ \to \R_+ and h>0h >0. We are mostly interested in the situation when the graph of gg is not dominated by its tangent line at zero, i.e. when the condition g(x)g(0)x,g(x) \leq g'(0)x, x0x \geq 0, is not satisfied. It is well known that, in such a case, a special type of rapidly decreasing wavefronts (pushed fronts) can appear in non-delayed equations (i.e. with h=0h=0). One of our main goals here is to establish a similar result for h>0h>0. We prove the existence of the minimal speed of propagation, the uniqueness of wavefronts (up to a translation) and describe their asymptotics at -\infty. We also present a new uniqueness result for a class of nonlocal lattice equations.Comment: 17 pages, submitte

    On the minimal speed of traveling waves for a non-local delayed reaction-diffusion equation

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    In this note, we give constructive upper and lower bounds for the minimal speed of propagation of traveling waves for non-local delayed reaction-diffusion equation.Наведено конструктивнi верхня i нижня межi поширення пересуваючих хвиль для нелокального реакцiйно-дифузiйного рiвняння з запiзненням

    On uniqueness of semi-wavefronts

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    Trofimchuk, S (reprint author), Univ Talca, Inst Matemat & Fis, Casilla 747, Talca, Chile.Motivated by the uniqueness problem for monostable semi-wave-fronts, we propose a revised version of the Diekmann and Kaper theory of a nonlinear convolution equation. Our version of the Diekmann-Kaper theory allows (1) to consider new types of models which include nonlocal KPP type equations (with either symmetric or anisotropic dispersal), nonlocal lattice equations and delayed reaction-diffusion equations; (2) to incorporate the critical case (which corresponds to the slowest wavefronts) into the consideration; (3) to weaken or to remove various restrictions on kernels and nonlinearities. The results are compared with those of Schumacher (J Reine Angew Math 316: 54-70, 1980), Carr and Chmaj (Proc Am Math Soc 132: 2433-2439, 2004), and other more recent studies
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