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Download or read book Viscosity Solutions of Hamilton-Jacobi Equations at the Boundary written by M. G. Crandall and published by . This book was released on 1984 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: At the classical level, when one considers boundary value problems for nonlinear scalar first order partial differential equations there are parts of the boundary where one does not expect to be able to prescribe boundary data. Likewise, uniqueness theorems can be proved for solutions which are prescribed only on parts of the boundary. However, globally defined classical solutions of first order nonlinear problems are rare, owing to the formation of shocks. This theoretical difficulty has recently been overcome for equations of Hamilton-Jacobi type via the development of the theory of viscosity solutions, a sort of generalized solution for which good existence and uniqueness theorems hold. This note is concerned, in the context of viscosity solutions, with identifying parts of the boundary which are irrelevant for a given equation from the point of view of requiring data in order to prove uniqueness. This involves knowing when a viscosity solution of an equation (in the viscosity sense) in the interior of the domain may be extended by continuity to a solution in the viscosity sense to points on the boundary. The results obtained to this effect are supplemented by examples delimiting their sharpness.