Moscow--Petersburg seminar on low-dimensional mathematics SPb, PDMI, 14.12.2001, 16:00--17:45, room 311 I.S.Krasilschik Geometry of differential equations and their algebraic invariants. Modern geometrical theory of differential equations treats an equation as a submanifold in a jet space endowed with a characteristic distribution, the so-called Cartan distribution. When one considers prolongations of a given equation, dimensions of the corresponding distributions tend to infinity. Nevertheless, at the top level (the infinite prolongation) this dimension "shrinks" to a finite number, the number of independent variables. For the majority of integrable systems this number is 2. We plan to present a concise review of the basic geometrical structures underlying differential equations and discuss their algebraic (mostly cohomological) invariants. ------------------------------------------------------ Seminar home page: http://www.pdmi.ras.ru/~duzhin/LDM/