April 6th, 2024
Breakfast 8:30 - 9:00 AM
9:00 - 9:20 AM
Haridas Kumar Das, Oklahoma State University
9:30 - 9:50 AM
John Michael Clark, University of Texas at Austin
10:00 - 10:20 AM
Hoai Dao, Oklahoma State University
Tea/Coffee 10:30 - 11:00 AM
11:00 - 11:20 AM
Preston Kelley, Oklahoma State University
11:30 AM - 12:20 PM
Tyler Labus, Oklahoma State University
Lunch Break 12:30 - 1:30 PM
1:30 - 1:50 PM
Abstract. Since Alexander proved that every holomorphic proper self map of the unit ball 𝔹n for n > 1 is an automorphism fifty years ago, classification of holomorphic proper maps between balls has stayed an active field of research. It is a classic result that the numerator of a rational proper map between balls achieves the degree of the map. We prove the analog result for rational proper maps between Siegel upper half spaces, another realization of the unit balls.
Abdullah Al Helal, Oklahoma State University
2:00 - 2:20 PM
Abstract. Elliptic operators are ubiquitous; they appear frequently in classical mechanics, quantum mechanics, and even in general relativity. This talk aims to explain ellipticity (somewhat generally) from scratch.
I will start with the classic definition of ellipticity for a single linear partial differential equation (PDE) in flat Euclidean space. Then we extend this definition to a system of linear PDEs via the notion of "principal symbols". Then the next step is to define ellipticity for linear operators on vector bundles over manifolds. In this stage, the geometric interpretation of symbols & ellipticity will be addressed. I will extend the notion of ellipticity one more time and explain the Nirenberg-Douglis ellipticity. If time permits, I will give an example from general relativity.
Siddiqur Rahman Milon, Oklahoma State University
2:30 - 2:50 PM
Abstract. Given an algebraic group G, a Borel subgroup B, and parabolic subgroup P containing B, there is a natural projection map from the flag variety G/B to the partial flag variety G/P. Associated to a flag variety is a Weyl group W, a combinatorial object indexing important subvarieties called Schubert varieties. Interesting in their own right, Schubert varieties also offer insights into Intersection Theory where their characteristic classes form a basis for the Grassmannian's cohomology ring. Richardson varieties are the pairwise intersection of Schubert varieties in general position. One of the most intriguing aspects of these subvarieties is how their geometric properties are often described by the combinatorics of the Weyl group. In this talk, we consider the restriction of the projection map to Richardson varieties and combinatorially describe when this restriction has equidimensional fibers.
Travis Grigsby, Oklahoma State University
Break 3:00 PM - 4:00 PM
4:00 - 5:00 PM
Geometry, Symmetry, and Spacetimes
Abstract. Sophus Lie invented what came to be known as Lie groups to study differential equations systematically. However, while his groups gained prominence in mathematics and physics, their original application to differential equations fell into obscurity for about half a century. General Relativity is considered the most nonlinear theory of nature, describing the gravitational field by a set of ten nonlinear second-order partial differential equations, the Einstein equations. Although relativists used Lie groups to idealize spacetimes from the beginning—which made Einstein's equations more tractable—applying Lie groups to study the "hidden" symmetries of Einstein's equations was not considered until Lie’s original ideas were revived and expanded in the 60s. This led to the search for solution generation techniques in general relativity in which one obtains a solution, or a family of solutions, from a "seed" solution that would otherwise be impossible to obtain. This talk will review static Einstein equations with axial symmetry in vacuum, i.e., Ricci-flat metrics with two commuting hypersurface-orthogonal Killing vector fields. It will present how such symmetries are useful in studying black holes and other spacetimes of current physical interest and present a recently found unexpected symmetry of the system.
Dr. Mohammad Akbar, University of Texas at Dallas
Dinner and Refreshments: 5:30 PM - 6:30 PM
Breakfast, Tea/Coffee and Dinner will be provided by MGSS