Global generalized solutions to a nonlinear Keller-Segel equation with singular sensitivity

Abstract

We consider the chemotaxis system \begin{eqnarray*} \begin{cases} \begin{array}{lll} \medskip u_t =Δu^m - \nabla(\frac{u}{v}\nabla v),&{} x\inΩ,\ t>0, \medskip v_t =Δv -uv,&{}x\inΩ,\ t>0, \medskip \frac{\partial u}{\partial ν}=\frac{\partial v}{\partialν}=0,&{}x\in\partialΩ,\ t>0, \medskip u(x,0)=u_0(x),\ v(x,0)=v_0(x), &{}x\inΩ, \end{array} \end{cases} \end{eqnarray*} in a smooth bounded domain $\Omega \subset {\mathbb{R}}^n$, $n\ge 2$. In this work it is shown that for all reasonably regular initial data $u_0\ge 0$ and $v_0>0$, the corresponding Neumann initial-boundary value problem possesses a global generalized solution provided that $m>1+\frac{n-2}{2n}$.

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