2017 Fall Colloquiums

Title: Central zeros of Clebsch-Gordan coefficients

Date: Wednesday, September 27, 2017

speaker: Dr. Robert W. Donley, Jr (QCC)

Time: 1pm—2pm

Room: S-213

Refreshments will be served

Abstract

Clebsch-Gordan coefficients play a central role in classical particle physics, representation theory, and special functions.  Based on Wigner's formula (1931), we give a new combinatorial procedure for computing these coefficients using Pascal's triangle.  These methods lead to a strong proof of a conjecture by Brudno and Rau on a certain vanishing condition.  In turn, nearby families of zeros are revealed and considered.  The overall program is joint work with Won Geun Kim and M. S. Ravi.

Title: Geometry of Hilbert schemes of points on algebraic surfaces

Date: Wednesday, October 11, 2017

speaker: Dr. Ruijie Yang (Stonybrook)

Time: 1pm—2pm

Room: S-213

Refreshments will be served

Abstract

Symmetric product of algebraic varieties is an important class in algebraic geometry. It's known classically that the symmetric product of a smooth algebraic curve is smooth. But they are singular for algebraic surfaces. Hilbert schemes of points provide a natural desingularization for these symmetric products. In this talk,  I will first discuss the geometry of symmetric products and Hilbert schemes of points on algebraic surfaces. Then I will talk about joint work with Tim Ryan about certain invariants associated to (nested) Hilbert schemes of points.

Title: On Orthogonal Gabor Bases Over \(\mathbb{Z}_p^d\)

Date: Wednesday, October 25, 2017

speaker: Dr. Azita Mayeli (Queensborough and the Graduate Center)

Time: 1pm—2pm

Room: S-213

Refreshments will be served

Abstract

After a quick introduction to the Gabor bases in classical settings \(\mathbb{R}^n\) and the motivation for studying them, I will introduce these bases in finite dimensional vector spaces over the finite cyclic of primes, i.e., \(\mathbb{Z}_p^d\). The study and investigation of these bases has analytic, number theoretic and combinatorial aspects. The analytic arguments come in the form of Fourier analytic inequalities, the number theoretic aspects involve the analysis of exponential sums and the combinatorial arguments involve tiling and the study of directions sets. 

Title: Outer Space

Date: Wednesday, November 8, 2017

speaker: Dr. Jonathon Funk (QCC

Time: 1pm—2pm

Room: S-213

Refreshments will be served

Abstract

George Bergman proves that an extended automorphism of a group must be inner.   We shall give a new proof of this fact, in an effort to match concepts of combinatorial group theory with categorical ones to some extent.   Then we enter Outer space by considering outer maps between finitely presented groups.  The new proof is helpful because we can adapt it to show that also an extended outer automorphism of a finitely presented group must be inner, so that its outer class is the identity.  In other words, the only extended outer automorphism is the trivial one.  These facts have geometric interpretations that I shall attempt to explain.  I will also try to explain the wider significance of the project.

Title: Quantum Theory and Group Representations

Date: Wednesday, November 15, 2017

speaker: Dr. Peter Woit (Columbia University)

Time: 1pm—2pm

Room: S-213

Refreshments will be served

Abstract

Some aspects of the relationship of quantum mechanics to the theory of unitary Lie group representations have been well-known since the early days of the subject.  The experience of teaching a course and writing a book aimed at explaining these relations made clear to me several parts of this story that I hadn't earlier appreciated.  In this talk I'll go over the general story of how quantum mechanics and group representation theory are related, emphasizing the simplest and most concrete examples. In addition, I'll try and explain some of the less well-known ideas about these relations which became clear to me and which others may perhaps find enlightening.

Title: Hedging a Long Term Supply Commitment with Short Term Futures Contracts

Date: Wednesday, November 29, 2017

speaker: Dr. Chunhui Yu (Farmingdale State College)

Time: 1pm—2pm

Room: S-213

Refreshments will be served

Abstract

Under the constraint of terminal risk, we search for an optimal deterministic strategy to reduce the running risk in hedging a long-term commitment with short-term futures contracts. An explicit solution is given if the underlying stock follows the simple stochastic differential equation \(dS_t=\mu dt+\sigma dB_t\), where \(B_t\)  is the standard Brownian motion. Our work generalizes the results of several previous researchers. Some related undergraduate research projects will also be introduced. 

 

Campus Cultural Centers

Kupferberg Holocaust Center (KHC)Opens in a new window
Kupferberg Holocaust Center Opens in a new window

Using the lessons of the Holocaust to educate current and future generations about the ramifications of unbridled prejudice, racism and stereotyping.

Queensborough Performing Arts CenterOpens in a new window
QPAC: Performing Arts CenterOpens in a new window

QPAC is an invaluable entertainment company in this region with a growing national reputation. The arts at QPAC continues to play a vital role in transforming lives and building stronger communities.

Queensborough Art GalleryOpens in a new window
QCC Art GalleryOpens in a new window

The QCC Art Gallery of the City University of New York is a vital educational and cultural resource for Queensborough Community College, the Borough of Queens and the surrounding communities.