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The second order estimate for the solution to a singular elliptic boundary value problem. (English) Zbl 1289.35078

Authors’ abstract: We study the second order estimate for the unique solution near the boundary to the singular Dirichlet problem \(-\Delta u=b(x)g(u)\), \(u>0\), \(x\in\Omega\), \(u| _{\partial\Omega}=0\), where \(\Omega\) is a bounded domain with smooth boundary in \(\mathbb R^N\), \(g\in C^1((0,\infty),(0,\infty))\), \(g\) is decreasing on \((0,\infty)\) with \(\lim_{s\to0^+}g(s)=\infty\) and \(g\) is normalized regularly varying at zero with index \(-\gamma\) (\(\gamma>1\)), \(b\in C^\alpha(\bar\Omega)\) (\(0<\alpha<1\)), is positive in \(\Omega\), may be vanishing on the boundary. Our analysis is based on Karamata regular variation theory.

MSC:

35J25 Boundary value problems for second-order elliptic equations
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