# The two membranes problem

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Daniela Da Silva, Columbia University
Fine Hall 314

We will consider the two membranes obstacle problem for two different operators, possibly non-local. In the case when the two operators have different orders, we discuss how to obtain $C^{1,\gamma}$ regularity of the solutions. In particular, for two fractional Laplacians of different orders, one obtains optimal regularity and a characterization of the boundary of the coincidence set. This is a joint work with L. Caffarellii and O. Savin.