Mathematics & Statistics Colloquium Tuesdays in DMTI 111

For virtual event links or to be added to the colloquium mailing list please contact

See also previous colloquium Abstracts and YouTube Playlist.

If interested in presenting to the Colloquium, please contact the organizers: Stephen D. Casey (, Nimai Mehta (

Fall 2022

Zeying WangTuesday, September 20, 3:15-4:15
DMTI 111 | Zoom (contact

Abstract : The research I will talk about is situated in the area of Combinatorial Design Theory, a subfield of Discrete Mathematics. In particular, I will focus on so-called partial difference sets (PDSs) in finite abelian groups. These are combinatorially defined subsets of a finite group that give rise to highly symmetric graphs called strongly regular Caley graphs. A few years ago we proved a theorem for strongly regular graphs that provides numerical restrictions on the number of fixed vertices and the number of vertices mapped to adjacent vertices under an automorphism. We then used this result to develop some new techniques to study regular partial difference sets in abelian groups. We have proved several non-existence results and classification results for partial difference sets in abelian groups. Also we completely answered a classical question from the 1990s: "For which odd positive integer v>1, can we find a Paley type partial difference set in an abelian group of order v?" In this talk I plan to give an overview of these results. The talk will be accessible to non-specialists.



Colloquium Videos

Catch up on some of our weekly colloquia.

Videos in this playlist

To play a specific video, use the playlist icon in the player or view each video on YouTube.

  1. AUcollege

    Experiencing Medieval Astronomy with an Astrolabe

  2. AUcollege

    Analytic Bezout Equations and Sampling in Rectangular and Radial Coordinates

  3. AUcollege

    Supporting the fight against the proliferation of chemicals weapons through cheminformatics

  4. AUcollege

    Multi-scale mechanistic modelling of the host defense in invasive aspergillosis

  5. AUcollege

    Double Reduction Estimation and Equilibrium Tests in Natural Autopolyploid Populations

  6. AUcollege

    Student Summer Research Experience Projects

  7. AUcollege

    Differential Privacy and the 2020 Census in the United States

  8. AUcollege

    Independent Component and Vector Analyses for Explainable Detection of Misinformation During High...

  9. AUcollege

    The Analysis of Periodic Point Processes

  10. AUcollege

    Weight calibration to improve efficiency for estimating pure absolute risks...

  11. AUcollege

    A Bilevel Optimization Method for an Exact Solution to Equilibrium Problems with Binary Variables

  12. AUcollege

    An Analysis of IQ-Link (TM)

  13. AUcollege

    Modeling Heat and Mass Transport in Cryobiology

  14. AUcollege

    Artistic mathematics: truth and beauty

  15. AUcollege

    Harnessing Dataset Complexity in Classification Tasks

  16. AUcollege

    Machine Learning Improves Estimates of Environmental Exposures

  17. AUcollege

    "Hitting Objects with Random Walks": John Nolan on Brownian Motion

  18. AUcollege

    Incorporating survival data to case-control studies with incident and prevalent cases

  19. AUcollege

    Statistical analysis of epidemic counts data

  20. AUcollege

    A New Architecture for Cell Phones, Sampling via Projection for UWB and AFB Systems

  21. AUcollege

    John Eltinge Talk

More Mathstat Events

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Capitol Dome Sinc FunctionDistrict Fourier Talks are the annual meeting of local mathematicians, engineers, and applied scientists exchanging and exploring recent advances and trends in harmonic analysis and applications.

Annual Halloween Lecture

Professor Henry Segerman of Oklahoma State University discusses his work in mathematical visualization.

Past Colloquia

  • Feb. 9, 2021: Sauleh Siddiqui (AU)
    "A Bilevel Optimization Method for an Exact Solution to Equilibrium Problems with Binary Variables" 
  • Feb. 16, 2021: Yei Eun Shin (NIH, NCI)
    "Weight calibration to improve efficiency for estimating pure absolute risks from the proportional and additive hazards model in the nested case-control design"
  • Feb. 23, 2021: Nate Strawn (Georgetown, NIH, NCI)
    "Isometric Data Embeddings: Visualizations and Lifted Signal Processing"
  • Mar. 16, 2021: Stephen D. Casey (AU, Personnel Data Research Institute)
    Thomas J. Casey (AU)
    "The Analysis of Periodic Point Processes"
  • Mar. 23, 2021: Zois Boukouvalas (AU)
    "Independent Component and Vector Analyses for Explainable Detection of Misinformation During High Impact Events"
  • Mar. 30, 2021: Der-Chen Chang (Georgetown)
    "Introduction to ̄∂-Neumann Problem"
  • Apr. 14, 2021: John M. Abowd (US Census Bureau)
    Title TBD

9/8/2020: Stephen D. Casey, American University; Norbert Wiener Center University of Maryland
A New Architecture for Cell Phones Sampling via Projection for UWB and AFB Systems

9/15/2020: Martha Dusenberry Pohl, American University 
Further Visualizations of the Census: ACS, Redistricting, Names Files; & HMDA using Shapefiles, BISG, Venn Diagrams, Quantification, 3-D rotation, & Animation

9/22/2020: Michael Baron, American University
Statistical analysis of epidemic counts data: modeling, detection of outbreaks, and recovery of missing data

9/29/2020: Soutrik Mandal, Division of Cancer Epidemiology and Genetics (National Cancer Institute, National Institutes of Health)
Incorporating survival data to case-control studies with incident and prevalent cases

10/13/2020: John P. Nolan, American University
Hitting objects with random walks

10/20/2020: Yuri Levin-Schwartz, Icahn School of Medicine at Mount Sinai 
Machine learning improves estimates of environmental exposures

10/27/2020: Nathalie Japkowicz, American University
Harnessing Dataset Complexity in Classification Tasks

11/10/2020: Anthony Kearsley, NIST

11/17/2020: Donna Dietz, American University 
An Analysis of IQ-Link (TM)

1/21/2020: Justin Pierce, Federal Reserve Washington DC
Examining the Decline in US Manufacturing Employment

1/28/2020: Ruth Pfeiffer, Biostatistics Branch, National Cancer Institution, NIH
Sufficient dimension reduction for high dimensional longitudinally measured biomarkers

2/11/2020: Erica L. Smith, Bureau of Justice Statistics, US Dept. of Justice
Overview of Department of Justice Statistical Data Collections Related to Gun Violence

2/18/2020: Sudip Bhatttacharjee, University of Connecticut
A Text Mining and Machine Learning Platform to Classify Businesses into NAICS codes

2/25/2020: Avi Bender, National Technical Information Service (NTIS)
Data Science Skills for Delivering Mission Outcome: An interactive discussion with the Director of the National Technical Information Service (NTIS), US Department of Commerce

9/10/2019: Dr. Scott Parker, American University
Some useful information about the Wilcoxon-Mann Whitney test and effect size measurement

9/17/2019: Dr. Michael Robinson, American University
Radio Fox Hunting using Sheaves

9/24/2019: Dr. Zois Boukouvalas, American University
Data Fusion in the Age of Data: Recent Theoretical Advances and Applications

10/8/2019: Dr. Elizabeth Stuart, Johns Hopkins
Assessing and enhancing the generalizability of randomized trials to target populations

10/15/2019: Latif Khalil, JBS International, Inc. 
Entity Resolution Techniques to Significantly Improve Healthcare Data Quality

10/22/2019: Dennis Lucarelli, American University 
Steering qubits, cats and cars via gradient ascent in function space

10/29/2019: Michael Thieme, Assistant Director for Decennial Census Programs, Systems and Contracts
Census 2020 - Clear Vision for the Country 

11/12/2019: John Eltinge, US Census Bureau 
Transparency and Reproducibility in the Design, Testing, Implementation and Maintenance of Procedures for the Integration of Multiple Data Sources

11/19/2019: Xander Faber, Institute for Defense Analyses, Center for Computing Sciences