Global existence and boundedness in a Keller-Segel-Stokes model with arbitrary porous medium diffusion

This paper deals with a boundary-value problem intwo-dimensional smoothly bounded domains for the coupledchemotaxis-fluid model$$ \left\{ \begin{array}{l} n_t+ u\cdot \nabla n=\Delta n^m - \nabla \cdot (n\chi(c)\nabla c)\\ c_t+ u\cdot \nabla c=\Delta c-nf(c)\\ u_t +\nabla P-\eta \Delta u+n \nabla \phi=0 \\ \nabla \cdot u=0, \end{array} \right.$$which describes the motion of oxygen-driven swimming bacteria in anincompressible fluid. The given functions $\chi$ and $f$ are supposed to besufficiently smooth and such that $f(0)=0$. It is proved that global bounded weak solutions exist whenever$m>1$ and the initial data $(n_0,c_0,u_0)$ are sufficiently regular satisfying$n_0 \ge 0$ and $c_0\ge 0$.This extends a recent result byDi Francesco, Lorz and Markowich (Discrete Cont. Dyn. Syst. A 28 (2010))which asserts global existence of weak solutions under the constraint $m \in (\frac{3}{2},2]$.