November 16 SPECIAL LOCATION 140 COE 2-3pm,
Jinjia Li,
Syracuse University
On nonrigidity of Frobenius
Abstract: In a commutative ring R of prime characteristic p, the Frobenius map is an endomorphism of R sending an element in R to its p-th
power. It is a very powerful tool in the study of commutative algebras and homological properties of algebras. The homological properties of the Frobenius map had
been studied for decades, starting with the work of Kunz which states that flatness of Frobenius detects the regularity of the ring. In this talk, I will discuss
the rigidity issue of the Frobenius map. In particular, I will talk about several surprising examples of Gorenstein local rings with nonrigid Frobenius, which are
quite different from the complete intersection case, where Frobenius is known to be rigid. These examples answer negatively a question raised by Avramov and Miller.
December 5,
Yongwei Yao,
Georgia State
An example of Hochster concerning Spec(Q[[x,y,z]]) (I)
Abstract:
We will present an example of Hochster that shows that the map SpecQ[[x,y,z]] to SpecQ[x,y,z] is not open.
The Georgia State University-University of South Carolina Commutative Algebra Seminar takes place twice every semester, the location alternating between Atlanta and
Columbia. For the upcoming seminar, go to
GSU-USC Commutative Algebra seminar .