10 Oct 2007; Mat-Nat Faculty (UiTø), room A228. Wednesday 10:15-12:00

Boris Kruglikov.

"Differential invariants: primer with examples".

Differential invariants are the basic objects of study for group actions on differential equations. They correspond to functions on the quotient spaces by symmetries. A short introduction to this fundamental area of differential geometry will be given, which is based on a series of joint works with V. Lychagin.

The exposition will be accompanied by a series of examples from Riemannian, almost complex and other geometries. I will explain how knowledge of invariants helps to solve equivalence and some other problems.