44 research outputs found

    Bistable Traveling Waves for Monotone Semiflows with Applications

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    This paper is devoted to the study of traveling waves for monotone evolution systems of bistable type. Under an abstract setting, we establish the existence of bistable traveling waves for discrete and continuous-time monotone semiflows. This result is then extended to the cases of periodic habitat and weak compactness, respectively. We also apply the developed theory to four classes of evolution systems

    Traveling waves and spreading speeds for time-space periodic monotone systems

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    The theory of traveling waves and spreading speeds is developed for time-space periodic monotone semiflows with monostable structure. By using traveling waves of the associated Poincar\'e maps in a strong sense, we establish the existence of time-space periodic traveling waves and spreading speeds. We then apply these abstract results to a two species competition reaction-advection-diffusion model. It turns out that the minimal wave speed exists and coincides with the single spreading speed for such a system no matter whether the spreading speed is linearly determinate. We also obtain a set of sufficient conditions for the spreading speed to be linearly determinate.Comment: arXiv admin note: text overlap with arXiv:1410.459

    Propagation Phenomena for A Reaction-Advection-Diffusion Competition Model in A Periodic Habitat

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    This paper is devoted to the study of propagation phenomena for a Lotka-Volterra reaction-advection-diffusion competition model in a periodic habitat. We first investigate the global attractivity of a semi-trival steady state for the periodic initial value problem. Then we establish the existence of the rightward spreading speed and its coincidence with the minimal wave speed for spatially periodic rightward traveling waves. We also obtain a set of sufficient conditions for the rightward spreading speed to be linearly determinate. Finally, we apply the obtained results to a prototypical reaction-diffusion model

    seasonal influence on age-structured invasive species with yearly generation

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    How do seasonal successions influence the propagation dynamics of an age-structured invasive species? We investigate this problem by considering the scenario that the offsprings are reproduced in spring and then reach maturation in fall within the same year. For this purpose, a reaction-diffusion system is proposed, with yearly periodic time delay and spatially nonlocal response caused by the periodic developmental process. By appealing to the recently developed dynamical system theories, we obtain the invasion speed cβˆ—c^* and its coincidence with the minimal speed of time periodic traveling waves. The characterizations of cβˆ—c^* suggest that (i) time delay decreases the speed and its periodicity may further do so; (ii) the optimal time to slow down the invasion is the season without juveniles; (iii) the speed increases to infinity with the same order as the square root of the diffusion rate

    Notes on nonlocal dispersal equations in a periodic habitat

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    In this paper, we prove that the solution maps of a large class of nonlocal dispersal equations are Ξ±\alpha-contractions, where Ξ±\alpha is the Kuratowski measure of noncompactness. Then we give some remarks on the spreading speeds and traveling waves for such evolution equations in a periodic habitat

    Competition in periodic media: I -- Existence of pulsating fronts

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    This paper is concerned with the existence of pulsating front solutions in space-periodic media for a bistable two-species competition--diffusion Lotka--Volterra system. Considering highly competitive systems, a simple "high frequency or small amplitudes" algebraic sufficient condition for the existence of pulsating fronts is stated. This condition is in fact sufficient to guarantee that all periodic coexistence states vanish and become unstable as the competition becomes large enough

    Analysis of Spreading Speeds with an Application to Cellular Neural Networks

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    In this paper, we focus on some properties of the spreading speeds which can be estimated by linear operators approach, such as the sign, the continuity and a limiting case which admits no spreading phenomenon. These theoretical results are well applied to study the effect of templates on propagation speeds for cellular neural networks (CNNs), which admit three kinds of propagating phenomenon.Comment: 19 pages, 9 figure

    Asymptotic convergence to pushed wavefronts in a monostable equation with delayed reaction

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    We study the asymptotic behaviour of solutions to the delayed monostable equation (βˆ—)(*): ut(t,x)=uxx(t,x)βˆ’u(t,x)+g(u(tβˆ’h,x)),u_{t}(t,x) = u_{xx}(t,x) - u(t,x) + g(u(t-h,x)), x∈R,Β t>0,x \in R,\ t >0, with monotone reaction term g:R+β†’R+g: R_+ \to R_+. Our basic assumption is that this equation possesses pushed traveling fronts. First we prove that the pushed wavefronts are nonlinearly stable with asymptotic phase. Moreover, combinations of these waves attract, uniformly on RR, every solution of equation (βˆ—)(*) with the initial datum sufficiently rapidly decaying at one (or at the both) infinities of the real line. These results provide a sharp form of the theory of spreading speeds for equation (βˆ—)(*).Comment: 27 pages, 1 figure, submitte

    Propagation Dynamics for Monotone Evolution Systems without Spatial Translation Invariance

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    In this paper,under an abstract setting we establish the existence of spatially inhomogeneous steady states and the asymptotic propagation properties for a large class of monotone evolution systems without spatial translation invariance. Then we apply the developed theory to study traveling waves and spatio-temporal propagation patterns for time-delayed nonlocal equations, reaction-diffusion equations in a cylinder, and asymptotically homogeneous KPP-type equations. We also obtain the existence of steady state solutions and asymptotic spreading properties of solutions for a time-delayed reaction-diffusion equation subject to the Dirichlet boundary condition

    Propagation Dynamics for a Spatially Periodic Integrodifference Competition Model

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    In this paper, we study the propagation dynamics for a class of integrodifference competition models in a periodic habitat. An interesting feature of such a system is that multiple spreading speeds can be observed, which biologically means different species may have different spreading speeds. We show that the model system admits a single spreading speed, and it coincides with the minimal wave speed of the spatially periodic traveling waves. A set of sufficient conditions for linear determinacy of the spreading speed is also given.Comment: arXiv admin note: text overlap with arXiv:1410.4591, arXiv:1504.0378
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