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In this paper we establish some conditional limit theorems for some critical superprocesses $X=\{X_t, t\ge 0\}$. First we identify the rate of non-extinction. Then we show that, for a large class of functions $f$, conditioned on…

Probability · Mathematics 2015-11-25 Yan-Xia Ren , Renming Song , Rui Zhang

Let $u$ be the solution of $u_t=\Delta\log u$ in $\R^N\times (0,T)$, N=3 or $N\ge 5$, with initial value $u_0$ satisfying $B_{k_1}(x,0)\le u_0\le B_{k_2}(x,0)$ for some constants $k_1>k_2>0$ where $B_k(x,t)…

Analysis of PDEs · Mathematics 2012-09-26 Kin Ming Hui , Sunghoon Kim

This paper is concerned with diffusion-reaction equations where the classical diffusion term, such as the Laplacian operator, is replaced with a singular integral term, such as the fractional Laplacian operator. As far as the reaction term…

Analysis of PDEs · Mathematics 2009-08-03 Cyril Imbert , Panagiotis E. Souganidis

We prove the growth rate of global solutions of the equation $u_t=\Delta u-u^{-\nu}$ in $\R^n\times (0,\infty)$, $u(x,0)=u_0>0$ in $\R^n$, where $\nu>0$ is a constant. More precisely for any $0<u_0\in C(\R^n)$ satisfying…

Analysis of PDEs · Mathematics 2008-08-07 Kin Ming Hui

We discuss conditions for well-posedness of the scalar reaction-diffusion equation $u_{t}=\Delta u+f(u)$ equipped with Dirichlet boundary conditions where the initial data is unbounded. Standard growth conditions are juxtaposed with the…

Analysis of PDEs · Mathematics 2011-03-25 James C. Robinson , Mikołaj Sierżęga

Second initial boundary problem in narrow domains of width $\epsilon\ll 1$ for linear second order differential equations with nonlinear boundary conditions is considered in this paper. Using probabilistic methods we show that the solution…

Probability · Mathematics 2010-11-30 Mark Freidlin , Konstantinos Spiliopoulos

The famous Fisher-KPP reaction diffusion model combines linear diffusion with the typical Fisher-KPP reaction term, and appears in a number of relevant applications. It is remarkable as a mathematical model since, in the case of linear…

Analysis of PDEs · Mathematics 2016-07-06 Alessandro Audrito , Juan Luis Vazquez

We study the blow-up question for the diffusion equation involving a nonlocal derivative in time defined by convolution with a nonnegative and nonincreasing kernel, and a nonlocal operator in space driven by a nonnegative radial L\'evy…

Analysis of PDEs · Mathematics 2024-06-21 Raúl Ferreira , Arturo de Pablo

In this paper, we study the problem of finding the solution of a multi-dimensional time fractional reactiondiffusion equation with nonlinear source from the final value data. We prove that the present problem is not well-posed. Then…

Analysis of PDEs · Mathematics 2020-03-17 Nguyen Huy Tuan , Tran Ngoc Thach , Donal O'Regan , Nguyen Huu Can

In [1], we showed contractivity of reaction-diffusion PDE: \frac{\partial u}{\partial t}({\omega},t) = F(u({\omega},t)) + D\Delta u({\omega},t) with Neumann boundary condition, provided \mu_{p,Q}(J_F (u)) < 0 (uniformly on u), for some 1…

Systems and Control · Computer Science 2012-10-09 Zahra Aminzare

This paper is devoted to studying propagation phenomena in integro-differential equations with a weakly degenerate non-linearity. The reaction term can be seen as an intermediate between the classical logistic (or Fisher-KPP) non-linearity…

Analysis of PDEs · Mathematics 2024-12-10 Emeric Bouin , Jérôme Coville , Xi Zhang

The paper studies the existence of solutions for the reaction-diffusion equation in $\mathbb R^2$ with point-interaction laplacian $\Delta_\alpha$ with $\alpha\in(-\infty,+\infty]$, assuming the functions to remain on the absolute…

Analysis of PDEs · Mathematics 2025-04-14 Daniele Barbera , Vladimir Georgiev , Mario Rastrelli

The stability of a thick planar premixed flame, propagating steadily in a direction transverse to that of unidirectional shear flow, is studied. A linear stability analysis is carried out in the asymptotic limit of infinitely large…

Fluid Dynamics · Physics 2024-06-28 Joel Daou , Prabakaran Rajamanickam

We consider a reaction-diffusion equation with a nonlinear term of the Fisher-KPP type, depending on time $t$ and admitting two limits as $t\to\pm\infty$. We derive the set of admissible asymptotic past and future speeds of transition…

Analysis of PDEs · Mathematics 2014-11-24 Francois Hamel , Luca Rossi

We study the time asymptotic propagation of solutions to the reaction-diffusion cooperative systems with fractional diffusion. We prove that the propagation speed is exponential in time, and we find the precise exponent of propagation. This…

Analysis of PDEs · Mathematics 2014-10-20 Anne-Charline Coulon , Miguel Yangari

This paper focuses on propagation phenomena in reaction-diffusion equations with a weaklymonostable nonlinearity. The reaction term can be seen as an intermediate between the classicallogistic one (or Fisher-KPP) and the standard weak Allee…

Analysis of PDEs · Mathematics 2023-12-18 Emeric Bouin , Jérôme Coville , Xi Zhang

We consider a reaction--diffusion equation in a domain consisting of two bulk regions connected via small channels periodically distributed within a thin layer. The height and the thickness of the channels are of order $\epsilon$, and the…

Analysis of PDEs · Mathematics 2020-07-09 Apratim Bhattacharya , Markus Gahn , Maria Neuss-Radu

We study the time evolution of a one-dimensional interacting fermion system described by the Luttinger model starting from a nonequilibrium state defined by a smooth temperature profile $T(x)$. As a specific example we consider the case…

Statistical Mechanics · Physics 2017-06-28 Edwin Langmann , Joel L. Lebowitz , Vieri Mastropietro , Per Moosavi

We investigate in this paper propagation phenomena for the heterogeneous reaction-diffusion equation $\partial_t u -\Delta u = f(t,u)$, $x\in R^N$, $t\in\R$, where f=f(t,u) is a KPP monostable nonlinearity which depends in a general way on…

Analysis of PDEs · Mathematics 2011-05-03 Grégoire Nadin , Luca Rossi

Reactive Rayleigh-Taylor systems are characterized by the competition between the growth of the instability and the rate of reaction between cold (heavy) and hot (light) phases. We present results from state-of-the-art numerical simulations…

Fluid Dynamics · Physics 2011-02-14 A. Scagliarini , L. Biferale , F. Mantovani , M. Sbragaglia , F. Toschi , R. Tripiccione