Calendar

Algebra and Number Theory Seminar  Questions or comments?

Posted April 7, 2019
Last modified April 8, 2019

This event has been rescheduled for 3:30 pm, Thursday, April 11, 2019

Peter Jorgensen, Newcastle University
Model categories of quiver representations

This is a report on joint work with Henrik Holm.

Let R be a k-algebra. Given a cotorsion pair (A,B) in Mod(R), Gillespie's Theorem shows how to construct a model category structure on C(Mod R), the category of chain complexes over Mod(R). There is an associated homotopy category H.

If (A,B) is the trivial cotorsion pair (projective modules, everything), then H is the derived category D(Mod R). Several other important triangulated categories can also be obtained from the construction.

Chain complexes over R are the Mod(R)-valued representations of a certain quiver with relations: Linearly oriented A double infinity modulo the composition of any two consecutive arrows. We show that Gillespie's Theorem generalises to arbitrary self-injective quivers with relations, providing us with many new model category structures.

Graduate Student Colloquium  

Posted April 10, 2019

Peter Jorgensen, Newcastle University
Quiver representations and homological algebra

Abstract: The word "quiver" means oriented graph: A graph where each edge has an orientation, i.e. is an arrow from one vertex to another. A representation of a quiver Q associates a vector space to each vertex of Q and a linear map to each arrow of Q. The representations of Q form a so-called abelian category. It is also possible to construct triangulated categories of quiver representations, and abelian and triangulated categories are the basic objects of homological algebra. The talk will consider a simple example and present a number of fundamental properties of abelian and triangulated categories of quiver representations. Refreshments will be served in the Keisler lounge from 3:00 to 3:30pm

Computational Mathematics Seminar  

Posted March 6, 2019
Last modified April 11, 2019

Hongchao Zhang, Louisiana State University
A Revisit of Gradient Descent Method for Nonlinear Optimization

In this talk, we will discuss some recent advances of the gradient methods developed in nonlinear optimization, including steepest descent methods, Barizilai-Borwein type methods, optimal gradient methods, quasi-Newton methods and conjugate gradient methods. Our focus will be the convergence properties of these methods as well as their practical performances.

Informal Geometry and Topology Seminar  Questions or comments?

Posted January 27, 2019

Natthawut Phanachet, Louisiana State University
TBA

Faculty Meeting  Questions or comments?

Posted April 16, 2019

Meeting of tenured faculty

Colloquium  Questions or comments?

Posted January 17, 2019

Jasson Vindas, Ghent University, Belgium
TBD

Conference  

Posted April 8, 2019

OAL-RAG 2019: Order, Algebra, Logic, and Real Algebraic Geometry

Further info at the conference website: https://www.math.lsu.edu/OAL-RAG2019