Optimal regularity of lower dimensional obstacle problems. (Russian, English) Zbl 1108.35038

Athanasopoulos, I.; Caffarelli, L. A.

J. Math. Sci., New York 132, No. 3, 274-284 (2006); translation from Zap. Nauchn. Semin. POMI 310, 49-66, 226 (2004).

The authors investigate the so-called “boundary obstacle problem”. They prove that solutions to this problem have the optimal regularity, \(C^{1,1/2}\), in any space dimension. This bound depends only on the local \(L^{2}\) norm of the solution. Main tools within the proof are the quasiconvexity of the solution and a monotonicity formula for an appropriate weighted average of the local energy of the normal derivative of the solution.

Reviewer: Jürgen Socolowsky (Brandenburg an der Havel)

MSC:

35J20	Variational methods for second-order elliptic equations
35B65	Smoothness and regularity of solutions to PDEs
35R35	Free boundary problems for PDEs

Keywords:

thin obstacle problem; optimal regularity; \(n\)-dimensional Signorini problem

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