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Zaizheng Li

Publications and source records attributed to Zaizheng Li.

4 recordsLinked to original sources

Bifurcation for the Lotka-Volterra competition model

We analyze the bifurcation phenomenon for the following two-component competition system: \begin{equation*} \begin{cases} -Δu_1=μu_1(1-u_1)-βαu_1u_2,& \text{in}\ B_1\subset \mathbb{R}^N, -Δu_2=σu_2(1-u_2)-βγu_1u_2,& \text{in}\ B_1\subset \mathbb{R}^N, \frac{\partial u_1}{\partial n}= \frac{\partial u_2}{\partial n} =0,&\text{on}\ \partial B_1, \end{cases} \end{equation*} where $N\ge 2$, $α>γ>0$, $σ\geμ>0$ and $β>\fracσγ$. More precisely, treating $β$ as the bifurcation parameter, we initially perform a local bifurcation analysis around the positive constant solutions, obtaining precise information of where bifurcation could occur, and determine the direction of bifurcation. As a byproduct, the instability of the constant solution is provided. Furthermore, we extend our exploration to the global bifurcation analysis. Lastly, under the condition $σ=μ$, we demonstrate the limiting configuration on each bifurcation branch as the competition rate $β\rightarrow+\infty$.

math.AP

Rotating spirals for three-component competition systems

We investigate the existence of rotating spirals for three-component competition-diffusion systems in $B_1\subset \mathbb{R}^2$: \begin{equation*} \begin{cases} \partial_tu_1-Δu_1=f(u_1)-βαu_1u_2-βγu_1 u_3,& \text{in}\ B_1\times \mathbb{R}^+, \partial_tu_2-Δu_2=f(u_2)-βγu_1u_2-βαu_2 u_3,& \text{in}\ B_1\times \mathbb{R}^+, \partial_tu_3-Δu_3=f(u_3)-βαu_1u_3-βγu_2 u_3,& \text{in}\ B_1\times \mathbb{R}^+, u_i(\textbf{x},0)=u_{i,0}(\textbf{x}), i=1,2,3, &\text{in} \ B_1, \end{cases} \end{equation*} with Neumann or Dirichlet boundary conditions, where $f(s)=μs(1-s)$, $μ, β>0$, $α>γ>0$. For the Neumann problem, we establish the existence of rotating spirals by applying the multi-parameter bifurcation theorem. As a byproduct, the instability of the constant positive solution is proved. In addition, for the non-homogeneous Dirichlet problem, the Rothe fixed point theorem is employed to prove the existence of rotating spirals.

math.AP

Long-time dynamics for the energy critical heat equation in $R^5$

We investigate the long-time behavior of global solutions to the energy critical heat equation in $R^5$ \begin{equation*} \begin{cases} \pp_t u=Δu+|u|^{\frac{4}{3}} u ~&\mbox{ in }~ R^5 \times (t_0,\infty), u(\cdot,t_0)=u_0~&\mbox{ in }~ R^5. \end{cases} \end{equation*} For $t_0$ sufficiently large, we show the existence of positive solutions for a class of initial value $u_0(x)\sim |x|^{-γ}$ as $|x|\rightarrow \infty$ with $γ>\frac32$ such that the global solutions behave asymptotically \begin{equation*} \| u(\cdot,t) \|_{L^\infty (\R^5)} \sim \begin{cases} t^{-\frac{3(2-γ)}{2}} ~&\mbox{ if }~ \frac32<γ<2 (\ln t)^{-3} ~&\mbox{ if }~ γ=2 1 ~&\mbox{ if }~ γ>2 \end{cases} \mbox{ \ for \ } t >t_0, \end{equation*} which is slower than the self-similar time decay $t^{-\frac{3}{4}}$. These rates are inspired by Fila-King \cite[Conjecture 1.1]{FilaKing12}.

math.AP

Sub-solutions and a point-wise Hopf's Lemma for Fractional p-Laplacian

We prove a Hopf's lemma in the point-wise sense. The essential technique is to prove $(-Δ)^s_p u(x)$ is uniformly bounded in the unit ball $B_1\subset\mathbb{R}^n$, where $u(x)=(1-|x|^2)^s_{+}$. Also we study the global Hölder continuity of bounded positive solutions for $(-Δ)^s_p u(x)=f(x,u).$

math.AP