


Mathematics Department
Virtual Commutative algebra seminar
Speaker: Shigeru Kuroda, Tokyo Metropolitan University, Hachioji, Japan
Date/Time: Friday, 23 December 2022, 5:30pm
Gmeet link: meet.google.com/wphnyzdhyj
Title: Z/pZactions on the affine space: classification, invariant ring, and plinth ideal
Abstract: Let k be a field of characteristic p>0. In this talk, we consider the Z/pZactions on the affine nspace over k, or equivalently the order p automorphisms of the polynomial ring k[X] in n variables over k. For example, every automorphism induced from a G_aaction is of order p. Hence, the famous automorphism of Nagata is of order p. Such an automorphism is important to study the automorphism group of the kalgebra k[X].
We discuss two topics: (1) classification, and (2) the relation between the polynomiality of the invariant ring and the principality of the plinth ideal. We also present some conjectures and open problems.
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