MATH 8583/4, THEORY OF PARTIAL DIFFERENTIAL EQUATIONS, 2003/4 11:15 - 12:05 MWF INSTRUCTOR: Mikhail Safonov VinH 231, tel. 5-8571, email: safonov@math.umn.edu We plan to cover the basic properties of different types of equations, with a more detailed account on second order elliptic and parabolic equations. We essentially use the classical maximum principle and energy estimates. In combination with local smoothness of harmonic functions or solutions to the heat equation, such estimates are used in the study of boundary value problems for elliptic and parabolic equations with Holder coefficients. This allows us to get the classical Schauder type results without using representations of solutions in terms of solid and layer potentials. This approach works also for fully nonlinear equations, for which no explicit representations of solutions are available. We will in details the qualitative properties of solutions to elliptic and parabolic equations, which do not depend on smoothness of coefficients (Holder regularity of solutions, Harnack inequalities, etc). These properties are very useful in the study of behavior of solutions near the boundary and at infinity, and in various free boundary problems. In Spring semester, we will also consider elliptic and parabolic equations in Sobolev classes (Calderon-Zygmund technique), and briefly hyperbolic equations and systems in different functional classes. PREREQUISITES: Some knowledge of Real and Functional Analysis (Lebesgue integral, Banach and Hilbert spaces). Lecture notes will be provided for the main part of the course. For supplementary reading, one can use the books: L. C. Evans, Partial Differential Equations, Graduate Studies inMathematics, Vol. 19, 1998. D. Gilbarg and N.S. Trudinger, Elliptic Partial Differential Equations of Second Order, Springer, 2nd Edition, 1983 or more recent 3rd Edition. N. V. Krylov, Lectures on Elliptic and Parabolic Equations in Holder spaces, Graduate Studies in Mathematics, Vol. 12, 1996.