Thursday, February 25 *JUNIOR COLLOQUIUM* TIME: 3:35 -- 4:25 p.m. ROOM: HBB 102 SPEAKER: Professor Grozdena Todorova TITLE: "Blow-up vs global existence" ABSTRACT: We will talk about: What is a partial differential equation (PDE)? Where do PDE's come from? What does it mean to ``solve'' a given PDE? There is a rich variety of physical phenomena which can be modeled by PDE's. Special attention will be paid to nonlinear Schrodinger equations which are modeling processes in nonlinear optics and laser physics. We will discuss phenomena related to the so called ``Blow-up'' of solutions, the rate of the blow up, how the blow-up can be arrested, singularity formations and instability. *Pizza will be available at 3:15 in AC 113A. *