On a quasilinear fully parabolic two-species chemotaxis system with two chemicals
Authors: Pan Xu , Wang Liangchen 
Published: February 2021

<p style='text-indent:20px;'>This paper deals with the following two-species chemotaxis system with nonlinear diffusion, sensitivity, signal secretion and (without or with) logistic source</p><p style='text-indent:20px;'><disp-formula> <label/> <tex-math id="FE1"> \begin{document}$ \begin{eqnarray*} \left\{ \begin{array}{llll} u_t = \nabla \cdot (D_1(u)\nabla u - S_1(u)\nabla v) + f_{1}(u),\quad &amp;x\in\Omega,\quad t&gt;0,\\ v_t = \Delta v-v+g_1(w),\quad &amp;x\in\Omega,\quad t&gt;0,\\ w_t = \nabla \cdot (D_2(w)\nabla w - S_2(w)\nabla z) + f_{2}(w),\quad &amp;x\in \Omega,\quad t&gt;0,\\ z_t = \Delta z-z+g_2(u),\quad &amp;x\in\Omega,\quad t&gt;0, \end{array} \right. \end{eqnarray*} $\end{document} </tex-math></disp-formula></p><p style='text-indent:20px;'>under homogeneous Neumann boundary conditions in a bounded domain <inline-formula><tex-math id="M1">\begin{document}$ \Omega\subset \mathbb{R}^n $\end{document}</tex-math></inline-formula> with <inline-formula><tex-math id="M2">\begin{document}$ n\geq2 $\end{document}</tex-math></inline-formula>. The diffusion functions <inline-formula><tex-math id="M3">\begin{document}$ D_{i}(s) \in C^{2}([0,\infty)) $\end{document}</tex-math></inline-formula> and the chemotactic sensitivity functions <inline-formula><tex-math id="M4">\begin{document}$ S_{i}(s) \in C^{2}([0,\infty)) $\end{document}</tex-math></inline-formula> are given by</p><p style='text-indent:20px;'><disp-formula> <label/> <tex-math id="FE2"> \begin{document}$ \begin{equation*} \begin{split} D_{i}(s) \geq C_{d_{i}} (1+s)^{-\alpha_i} \quad \text{and} \quad 0 &lt; S_{i}(s) \leq C_{s_{i}} s (1+s)^{\beta_{i}-1} \text{ for all } s\geq0, \end{split} \end{equation*} $\end{document} </tex-math></disp-formula></p><p style='text-indent:20px;'>where <inline-formula><tex-math id="M5">\begin{document}$ C_{d_{i}},C_{s_{i}}&gt;0 $\end{document}</tex-math></inline-formula> and <inline-formula><tex-math id="M6">\begin{document}$ \alpha_i,\beta_{i} \in \mathbb{R} $\end{document}</tex-math></inline-formula> <inline-formula><tex-math id="M7">\begin{document}$ (i = 1,2) $\end{document}</tex-math></inline-formula>. The logistic source functions <inline-formula><tex-math id="M8">\begin{document}$ f_{i}(s) \in C^{0}([0,\infty)) $\end{document}</tex-math></inline-formula> and the nonlinear signal secretion functions <inline-formula><tex-math id="M9">\begin{document}$ g_{i}(s) \in C^{1}([0,\infty)) $\end{document}</tex-math></inline-formula> are given by</p><p style='text-indent:20px;'><disp-formula> <label/> <tex-math id="FE3"> \begin{document}$ \begin{equation*} \begin{split} f_{i}(s) \leq r_{i}s - \mu_{i} s^{k_{i}} \quad \text{and} \quad g_{i}(s)\leq s^{\gamma_{i}} \text{ for all } s\geq0, \end{split} \end{equation*} $\end{document} </tex-math></disp-formula></p><p style='text-indent:20px;'>where <inline-formula><tex-math id="M10">\begin{document}$ r_{i} \in \mathbb{R} $\end{document}</tex-math></inline-formula>, <inline-formula><tex-math id="M11">\begin{document}$ \mu_{i},\gamma_{i} &gt; 0 $\end{document}</tex-math></inline-formula> and <inline-formula><tex-math id="M12">\begin{document}$ k_{i} &gt; 1 $\end{document}</tex-math></inline-formula> <inline-formula><tex-math id="M13">\begin{document}$ (i = 1,2) $\end{document}</tex-math></inline-formula>. With the assumption of proper initial data regularity, the global boundedness of solution is established under the some specific conditions with or without the logistic functions <inline-formula><tex-math id="M14">\begin{document}$ f_{i}(s) $\end{document}</tex-math></inline-formula>.</p><p style='text-indent:20px;'>Moreover, in case <inline-formula><tex-math id="M15">\begin{document}$ r_{i}&gt;0 $\end{document}</tex-math></inline-formula>, for the large time behavior of the smooth bounded solution, by constructing the appropriate energy functions, under the conditions <inline-formula><tex-math id="M16">\begin{document}$ \mu_{i} $\end{document}</tex-math></inline-formula> are sufficiently large, it is shown that the global bounded solution exponentially converges to <inline-formula><tex-math id="M17">\begin{document}$ \left((\frac{r_{1}}{\mu_{1}})^{\frac{1}{k_{1}-1}}, (\frac{r_{2}}{\mu_{2}})^{\frac{\gamma_{1}}{k_{2}-1}}, (\frac{r_{2}}{\mu_{2}})^{\frac{1}{k_{2}-1}}, (\frac{r_{1}}{\mu_{1}})^{\frac{\gamma_{2}}{k_{1}-1}}\right) $\end{document}</tex-math></inline-formula> as <inline-formula><tex-math id="M18">\begin{document}$ t\rightarrow\infty $\end{document}</tex-math></inline-formula>.</p>