Wednesday, January 28, 2009. Minnesota PDE seminar Speaker: Professor Peter Polacik, University of Minnesota. Title: Parabolic Liouville theorems and their applications. Abstract: Parabolic Liouville theorems state that if u is an entire solution of a specific parabolic equation (semilinear heat equation with power nonlinearity) and u is contained in an admissible class of functions, then u is necessarily the trivial solution. After a discussion of available Liouville theorems for nonnegative solutions, we shall focus on a Liouville theorem for radial sign-changing solutions. Among applications, we shall mention universal a priori estimates of solutions and a construction of infinitely many periodic solutions of periodic-parabolic boundary value problems. **************************************************************************************