# Graduate Seminar

Current contact: Brandi Henry and Ruth Meadow-MacLeod

The seminar takes place on Fridays from 3:00 to 4:00pm on Zoom, and there will be a social time from 2:00 to 3:00pm in lieu of the refreshments usually offered.

• Friday November 13, 2020 at 15:00,
Infinite Time Solutions of Numerical Schemes for Advection Problems

Abhijit Biswas, Temple University

Abstract: Solving advection problems accurately for a large number of time steps plays an important role. We can think of this as a sub-problem to solve moving interface problems, time-dependent Navier-Stokes or radiative transfer. In this talk, I will present a method called jet scheme with nonlinear interpolation, which can produce accurate solutions over a large number of time steps.

• Friday November 6, 2020 at 15:00,
Expansion properties of graphs and a few incidences of such properties.

Tantrik Mukerji, Temple University

Abstract: We say that a graph is very well connected if you can roughly remove a number of edges from any subset and the graph would still be connected. There is a formulation of such a property called the Cheeger constant. Also, one is interested in constructing families of d-regular graphs with Cheeger constant bounded from below these are known as expander families and are of relevance to mathematicians and computer scientists. I will just lightly survey the first construction of the most optimal of such families due to Lubotzky, Phillips, and Sarnak and a more recent construction by Marcus, Spielman, and Srivastava. The survey will be very light with no proofs given.

• Friday October 30, 2020 at 15:00,
The Dixmier-Moeglin equivalence for algebras

Ramy Yammine, Temple University

Abstract: When studying the representation theory of an algebra A, one usually tries to understand the irreducible representations of A. This tends to be a rather daunting task. As a starting point, one can try to understand the kernels of the irreducible representations of A, which are a special subclass of prime ideals, called primitive ideals. When it holds, the Dixmier-Moeglin equivalence gives various characterizations of primitivity, that are topological and ring theoretic, expanding the tools with which one can study primitive ideals. In this talk, I will explain the equivalence and give examples of algebras for which it holds. If time permits, I will mention how actions of various algebraic structures on an algebra A can be useful in proving the equivalence.

• Friday October 23, 2020 at 15:00,
Quantum search algorithms on random graphs

Alex Ahn, Temple University

Abstract: Since the discovery of Shor's algorithm in 1994, quantum computing has been advertised as the next big revolution in computer science as well as in quantum chemistry and cryptography. In this talk, I will introduce Grover's algorithm and its extension as a search algorithm on general graphs. I will discuss ways in which the promise of quantum computing has been exaggerated, and ways in which we may expect to see substantive contributions from the field to our understanding of complexity theory. Finally, I will demonstrate some recent results from simulations of quantum search on random graphs.

• Friday October 16, 2020 at 15:00,
On the Poisson Kernel for the Laplacian in the Upper Half-Space

Jeongsu Kyeong, Temple University

Abstract: In this talk, I will discuss fundamental properties of the Poisson kernel for the Laplacian in the upper half-space and its role in establishing well-posedness for the Dirichlet problem for the Laplace operator with $L^p$ data, $1 < p < \infty$ , in this geometric setting. More specifically I will describe the notions of non-tangential maximal operator and non-tangential trace and explore these concepts in the context of convolutions of the Poisson kernel and $L^p$ integrable functions.

• Friday October 9, 2020 at 14:00,
An Exploration of the Curve Complex

Brandis Whitfield, Temple University

Abstract: Given a surface S, its associated curve complex, $\mathcal{C}$(S), is a simplicial complex which encodes topological information on the set of homotopy classes of S. In this talk, we'll explore combinatorial properties of its underlying graph and its value to the topology, geometry and mapping class group of a hyperbolic surface.

• Friday October 2, 2020 at 15:00,
The Thurston geometries

DB Choi, Temple University

Abstract: We'll talk about the eight 3-dimensional Thurston geometries (E^3, S^3, H^3, S^2×R, H^2×R, Nil, universal cover of SL_2(R), Solv) and how they can be understood. We will state the theorem known as the Geometrization Conjecture which classifies 3-dimensional manifolds with the 8 model geometries.

• Friday September 25, 2020 at 15:00,
Quasiautomorphism Groups of Type F∞

Delaney Aydel, Temple University

Abstract: The groups QF, QT, and QV are quasiautomorphism groups of the infinite binary tree, so named due to their similarity with Thompson's groups F, T, and V. In this talk, we will describe QF, QT, and QV in two ways: as quasiautomorphism groups and as diagram groups over semigroup presentations. Our goal is to show these groups have type F

This project is joint work with Dan Farley and Sam Audino.

• Friday September 18, 2020 at 15:00,
A Journey Through Computational Neuroscience

James Rosado, Temple University

Abstract: In this talk, we will discuss the Hodgkin-Huxley equations for modelling the electrical dynamics of a neuron, the PDE equations for modelling the Calcium Dynamics within a neuron, and applications in repetitive Transcranial magnetic stimulation (rTMS). If time permits we will demonstrate some of the results from numerical experiments.

• Friday September 11, 2020 at 15:00,
Left Ordering of Group

Khanh Le, Temple University

Abstract: In this talk, we will discuss left ordering of a group. We will focus on basic examples of groups which admit a left order and properties of the space of left orders. If time permits, we discuss some interesting questions and connections of left ordering on groups to 3-manifold topology.

• Friday April 17, 2020 at 13:00, Wachman 617
Alexander Ahn, Temple University

• Friday April 10, 2020 at 13:00, Wachman 617
Thomas Ng, Temple University

• Friday April 3, 2020 at 13:00, Wachman 617
Chia-Han Chou, Temple University

• Friday March 27, 2020 at 13:00, Wachman 617
Najmeh Salehi, Temple University

• Friday March 13, 2020 at 13:00, Wachman 617
Asynchronous algorithms

Xinli Yu, Temple University

Abstract: With the advent of parallel computers, many new algorithms were devised or rediscovered for the new architectures. Asynchronous parallel solvers are new techniques that speed up thecomputation time. The main character of asynchronous algorithm is that the local algorithms donot have to wait at predetermined points for predetermined messages to become available. Asynchronous method has wide applications. In this talk applications of asynchronous iterations todifferent areas will be discussed.

• Friday February 21, 2020 at 13:00, Wachman 617
The Mathematics of Gerrymandering

Rose Kaplan-Kelly, Temple University

Abstract: Based on the work of Moon Duchin.

• Friday February 14, 2020 at 13:00, Wachman 617
Techniques for parameter sensitivity analysis of mathematical modeling

Zhi Li, Temple University

Abstract: Understanding the significance and sensitivity of parameters plays an important role in mathematical modeling. A sensitivity analysis of the parameters is not only critical to model validation but also serves to guide future research efforts. We will talk about several of the more practical methods for conducting parameter sensitivity studies, ranging from one-at-a-time sensitivity measures to standardized regression coefficients to statistical tests.

• Friday February 7, 2020 at 13:00, Wachman 617
Graduating Grad Student Panel

A panel of soon-to-graduate grad students will describe their experiences and give their advice on how to approach the penultimate and the last years of the PhD program at Temple, including the required paperwork, the job market, and the dissertation process.

• Friday January 31, 2020 at 13:00, Wachman 617
Dr. Joan Birman and the Jones Polynomial

Katherine Burke, Temple University

Abstract: Come one, come all, and learn about the pros and cons of the Jones polynomial as an invariant of a closed 3-braid link.  Based Birman’s ‘85 On the Jones Polynomial of Closed 3 Braids.

• Friday January 24, 2020 at 13:00, Wachman 617
Triangle groups and their behavior on surfaces

Rebekah Palmer, Temple University

Abstract: The tessellation of surfaces is an ongoing question. A healthy place to start is with a class of relatively uncomplicated tiles — triangles! We construct the triangle groups geometrically by reflecting triangles across their three edges and propagating. From here, we can express the group as an algebraic structure. We will explore what properties can be deduced about these groups in both geometric and algebraic contexts as well as the grander implications of how we approach tiling surfaces.

• Friday January 17, 2020 at 12:00, Wachman 617
Welcome back