Global classical solutions, stability of constant equilibria, and spreading speeds in attraction-repulsion chemotaxis systems with logistic source on $\mathbb{R}^{N}$

Abstract

We consider the following chemotaxis systems $$\begin{cases}u_t=Δu-χ_1\nabla(u\nabla v_1)+χ_2\nabla(u\nabla v_2)+u(a-bu),\ \ x\in\mathbb R^N,t>0,\\0=(Δ-λ_1I)v_1+μ_1u,\ \ x\in\mathbb R^N,t>0,\\0=(Δ-λ_2I)v_2+μ_2u,\ \ \text{in}\ x\in\mathbb R^N,\ t>0,\\u(\cdot,0)=u_0,\ \ x\in\mathbb R^N,\end{cases}$$where $χ_i,\ λ_i,\ μ_i,\ i=1,2$ and $a,\ b$ are positive constant real numbers and $N$ is a positive integer. Under some conditions on the parameters, we prove the global existence and boundedness of classical solutions $(u(x,t;u_0),v_1(x,t;u_0),v_2(x,t;u_0))$ for nonnegative, bounded, and uniformly continuous initials $u_0(x)$. Next, we show that, for every strictly positive initial \,$u_0(x)$,$$\lim_{t\to\infty}\left[\|u(\cdot,t;u_0)-\frac{a}{b}\|_{\infty}+\|λ_1v_1(\cdot,t;u_0)-\frac{a}{b}μ_1\|_{\infty}+\|λ_2v_2(\cdot,t;u_0)-\frac{a}{b}μ_2\|_{\infty}\right]=0.$$ Finally, we explore the spreading properties of the global solutions and prove that there are two positive numbers $0 c^*_+(χ_1,μ_1,λ_1,χ_2,μ_2,λ_2)$. Furthermore we show that$$\lim_{(χ_1,χ_2)\to(0,0)}c^*_-(χ_1,μ_1,λ_1,χ_2,μ_2,λ_2)=\lim_{(χ_1,χ_2)\to(0,0)}c^*_+(χ_1,μ_1,λ_1,χ_2,μ_2,λ_2)=2\sqrt{a}.$$