Title: An adaptive method for Hamilton-Jacobi equations Bernardo Cockburn Department of Mathematics University of Minnesota 127 Vincent Hall, 206 Church St. S.E. Minneapolis, MN 55455 USA Email: cockburn@math.umn.edu Web page: www.math.umn.edu/~cockburn Abstract: In this talk, we present the first adaptive method for finding approximations for Hamilton-Jacobi equations whose $L^\infty$-distance to the viscosity solution is no bigger than a prescribed tolerance. The method proceeds as follows. On any given mesh, the approximate solution is computed by using a well known monotone scheme; then, the quality of the approximation is tested by using an approximate a posteriori error estimate. If the error is bigger than the prescribed tolerance, a new mesh is computed by solving a suitably devised differential equation. A thorough numerical study of the method is performed which shows that rigorous error control is achieved, even though only an approximate a posteriori error estimate is used; the method is thus reliable. Furthermore, the numerical study also shows that the method is efficient and that it has an optimal computational complexity. These properties are independent of the value of the tolerance.