TY - JOUR

T1 - Radial solutions to a chemotaxis-consumption model involving prescribed signal concentrations on the boundary

AU - Lankeit, Johannes

AU - Winkler, Michael

PY - 2021/12/14

Y1 - 2021/12/14

N2 - The chemotaxis system \begin{align*} u_t &= \Delta u - \nabla \cdot (u\nabla v), \\ v_t &= \Delta v - uv, \end{align*} is considered under the boundary conditions \(\frac{\partial u}{\partial\nu}- u\frac{\partial v}{\partial\nu}=0\) and \(v=v_\star\) on \(\partial\Omega\), where \(\Omega\subset\mathbb{R}^n\) is a ball and \(v_\star\) is a given positive constant. In the setting of radially symmetric and suitably regular initial data, a result on global existence of bounded classical solutions is derived in the case \(n=2\), while global weak solutions are constructed when \(n\in \{3,4,5\}\). This is achieved by analyzing an energy-type inequality reminiscent of global structures previously observed in related homogeneous Neumann problems. Ill-signed boundary integrals newly appearing therein are controlled by means of spatially localized smoothing arguments revealing higher order regularity features outside the spatial origin. Additionally, unique classical solvability in the corresponding stationary problem is asserted, even in nonradial frameworks.

AB - The chemotaxis system \begin{align*} u_t &= \Delta u - \nabla \cdot (u\nabla v), \\ v_t &= \Delta v - uv, \end{align*} is considered under the boundary conditions \(\frac{\partial u}{\partial\nu}- u\frac{\partial v}{\partial\nu}=0\) and \(v=v_\star\) on \(\partial\Omega\), where \(\Omega\subset\mathbb{R}^n\) is a ball and \(v_\star\) is a given positive constant. In the setting of radially symmetric and suitably regular initial data, a result on global existence of bounded classical solutions is derived in the case \(n=2\), while global weak solutions are constructed when \(n\in \{3,4,5\}\). This is achieved by analyzing an energy-type inequality reminiscent of global structures previously observed in related homogeneous Neumann problems. Ill-signed boundary integrals newly appearing therein are controlled by means of spatially localized smoothing arguments revealing higher order regularity features outside the spatial origin. Additionally, unique classical solvability in the corresponding stationary problem is asserted, even in nonradial frameworks.

KW - math.AP

KW - 35K55 (primary), 35J61, 35Q92, 92C17 (secondary)

UR - http://www.scopus.com/inward/record.url?scp=85122755405&partnerID=8YFLogxK

U2 - 10.1088/1361-6544/ac3c2b

DO - 10.1088/1361-6544/ac3c2b

M3 - Article

VL - 35

SP - 719

EP - 749

JO - Nonlinearity

JF - Nonlinearity

SN - 0951-7715

IS - 1

ER -