Date:	Mon, March 4, 2013
Time:	17:15
Place:	Research II Lecture Hall

Abstract: Hilbert's 14th problem is a question in invariant theory. Namely, given a finitely generated algebra over some field k and a group acting on the algebra by k-automorphisms, is the ring of invariant elements finitely generated, too? Whereas the answer is "no" in general, there are positive answers for some groups, special kinds of actions or some algebras, and even open problems for special situations. We start with an overview of existing results. We will then go into more details for solved and nonsolved problems for the additive group G_a with an emphasis on positive characteristic.