8 June 2006; Mat-Nat Faculty (UiTø), room U1=A228. Thursday 10:15-12:00

Nail H. Ibragimov (ALGA & Blekinge Institute of Technology, Sweden)

"Invariants of linear and non-linear equations"

A unified method for determining invariants of families of equations possessing finite or infinite equivalence groups will be discussed. The method is based on the infinitesimal approach and is applicable to algebraic and differential equations (ordinary and partial, linear or non-linear).

The present talk is aimed at discussing the main principles of the method and its applications to solution of Laplace’s problem on determination of all invariants of hyperbolic and elliptic equations.