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Global existence and boundedness to a two-species chemotaxis-competition model with singular sensitivity
Journal of Evolution Equations ( IF 1.1 ) Pub Date : 2020-03-25 , DOI: 10.1007/s00028-020-00570-5
Shuyan Qiu , Chunlai Mu , Xinyu Tu , Hong Yi

In the present study, we investigate the chemotaxis-consumption system of two competing species which are attracted by the same signal substance

$$\begin{aligned} \left\{ \begin{array}{llll} u_t=\Delta u-\chi _1\nabla \cdot (\frac{u}{w}\nabla w)+u(a_1-b_1u-c_1v),&{}\quad x\in \Omega ,\quad t>0,\\ v_t=\Delta v-\chi _2\nabla \cdot (\frac{v}{w}\nabla w)+v(a_2-b_2v-c_2u),&{}\quad x\in \Omega ,\quad t>0,\\ w_t=\Delta w-(\alpha u+\beta v)w,&{}\quad x\in \Omega ,\quad t>0, \end{array} \right. \end{aligned}$$

associated with homogeneous Neumann boundary conditions in a smooth bounded domain \(\Omega \subset R^{n}(n\ge 1)\), where the parameters \(\alpha \), \(\beta \), \(\chi _i\), \(a_i\), \(b_i\), \(c_i\), \(i=1, 2\) are supposed to be positive. When \(n=1\), it is shown that whenever the initial data \((u_0, v_0, w_0)\) are positive and suitably regular, the associated initial-boundary value problem admits a globally defined bounded classical solution for any \(\chi _i\), \(b_i>0\, (i =1,2)\). When \(n=2\), we establish that if \(\max \{\chi _1, \chi _2\}<1\), then the global solution exists regardless of the sizes of \(b_1>0\) and \(b_2>0\), or if \(\min \{\chi _1, \chi _2\}\ge 1\), then there are \(b^*_i(\chi _i)\,(i =1,2)>0\) such that the global classical solution also exists when \(b_i>b^*_i(\chi _i)\,(i =1,2)\) . Moreover, the global boundedness of the classical solution is determined as well, that is, there exist \(\lambda _i(\Omega )>0\) and \(\gamma _i(\Omega )>0\) such that the global solution (uvw) is uniformly bounded in time provided that \(b_i>\lambda _i(\Omega )a_i+\gamma _i(\Omega )\) for \(\max \{\chi _1, \chi _2\}<1\) or \(b_i>\{b^*_i(\chi _i), \lambda _i(\Omega )a_i+\gamma _i(\Omega )\}\) for \(\min \{\chi _1, \chi _2\}\ge 1\) with \(i=1,2\), respectively. Furthermore, when \(n\ge 3\), the corresponding initial-boundary value problem possesses a unique global classical solution under the conditions that \(\max \{\chi _1, \chi _2\}<\sqrt{\frac{2}{n}}\) and \(\min \{\frac{b_1}{3\alpha +\beta }, \frac{b_2}{\alpha +3\beta }\}>\frac{n-2}{4n}\).



中文翻译:

具有奇异敏感性的两种种群趋化竞争模型的全局存在性与有界性

在本研究中,我们研究了两个竞争物种被同一信号物质吸引的趋化-消耗系统

$$ \ begin {aligned} \ left \ {\ begin {array} {llll} u_t = \ Delta u- \ chi _1 \ nabla \ cdot(\ frac {u} {w} \ nabla w)+ u(a_1- b_1u-c_1v),&{} \ quad x \ in \ Omega,\ quad t> 0,\\ v_t = \ Delta v- \ chi _2 \ nabla \ cdot(\ frac {v} {w} \ nabla w) + v(a_2-b_2v-c_2u),&{} \ quad x \ in \ Omega,\ quad t> 0,\\ w_t = \ Delta w-(\ alpha u + \ beta v)w,&{} \ quad x \ in \ Omega,\ quad t> 0,\ end {array} \ right。\ end {aligned} $$

与光滑有界域\(\ Omega \ subset R ^ {n}(n \ ge 1)\)中的齐次Neumann边界条件相关,其中参数\(\ alpha \)\(\ beta \)\( \ chi _i \)\(a_i \)\(b_i \)\(c_i \)\(i = 1,2 \)应该是正数。当\(n = 1 \)时,表明只要初始数据\((u_0,v_0,w_0)\)为正且适当地规则,相关联的初始边界值问题就允许对任何\(\ chi _i \)\(b_i> 0 \,(i = 1,2)\)。当\(n = 2 \),我们确定如果\(\ max \ {\ chi _1,\ chi _2 \} <1 \),则存在全局解决方案,而与\(b_1> 0 \)\(b_2> 0 \)的大小无关,或者\\\ min \ {\ chi _1,\ chi _2 \} \ ge 1 \),则存在\(b ^ * _ i(\ chi _i)\,(i = 1,2)> 0 \ ),这样当\(b_i> b ^ * _ i(\ chi _i)\,(i = 1,2)\)时也存在全局经典解。此外,经典溶液的全球有界被确定为好,即,存在\(\拉姆达_i(\欧米茄)> 0 \)\(\伽马_i(\欧米茄)> 0 \) ,使得所述全局解(u,  v,  w)在时间上是一致的,只要\(b_i> \ lambda _i(\ Omega)a_i + \ gamma _i(\ Omega)\)表示\(\ max \ {\ chi _1,\ chi _2 \} <1 \)\(b_i> \ {b ^ * _i(\ chi _i),\ lambda _i(\ Omega)a_i + \ gamma _i(\ Omega} \} \)对于\(\ min \ {\ chi _1,\ chi _2 \} \ ge 1 \)\ (i = 1,2 \)分别。此外,当\(n \ ge 3 \)时,对应的初始边界值问题在\(\ max \ {\ chi _1,\ chi _2 \} <\ sqrt {\ frac {2} {n}} \)\(\ min \ {\ frac {b_1} {3 \ alpha + \ beta},\ frac {b_2} {\ alpha +3 \ beta} \}> \ frac {n -2} {4n} \)

更新日期:2020-03-25
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