Northeastern University, Department of Mathematics
Organizers: Adam Ding, Ken Duffy, Paul Hand, Eugene Tang, He Wang
*For remote/hybrid meetings, Zoom link will be sent by email upon request. Contact He Wang at he.wang@northeastern.edu
The seminar features talks in Applied and Interdisciplinary Mathematics (AIM) by our own faculty as well as faculty from other departments at Northeastern and other universities. For additional information or to be added to the mailing list, please contact He Wang.
Note: The time and location of the seminar are not fixed!
Upcoming Talks
Date: Thursday, October 9, 2025 Time: 2:00 pm Location: Seminar room EXP-610 Speaker: Marco Pacini (University of Trento & Fondazione Bruno Kessler, visiting Northeastern University) Title: On Universality of Equivariant Neural Networks Abstract: Equivariant neural networks provide a principled way to incorporate symmetry into learning architectures and are studied for both their empirical success and mathematical structure. In this talk, we first discuss their separation power—the ability to distinguish inputs up to symmetry—which is a well-understood and necessary condition for approximation. We then examine their approximation capabilities, which remain less well understood. Focusing on equivariant shallow networks, we show that architectures with the same separation power may nevertheless approximate different classes of functions, demonstrating that separation is a necessary but not sufficient condition for universality. The talk is based on joint works with Xiaowen Dong, Bruno Lepri, Gabriele Santin, Shubhendu Trivedi, Mircea Petrache and Robin Walters. Biography: Marco Pacini’s research focuses on the fundamental principles of Geometric Deep Learning and Equivariant Machine Learning. Some of his research interests include the constructive characterization of equivariant models, as well as their expressivity and approximation capabilities. |
Date: Thursday, October 16, 2025 Time: 2:00 pm Location: Seminar room EXP-701A Speaker: Willie Harrison (Brigham Young University) Title: TBA Abstract: TBA Biography: Willie Harrison graduated from Utah State University in 2007 with his MS in Electrical Engineering and from the Georgia Institute of Technology in 2012 with his PhD is Electrical and Computer Engineering. In 2012, he joined the faculty of the University of Colorado, Colorado Springs as an Assistant Professor, and he has been with the BYU Electrical and Computer Engineering Department since 2017. At UCCS, he served on the proposal, instructor search, graduate fellowship selection, and Internationalization Advisory committees, and he additionally served as faculty advisor to the IEEE student club. He earned the Teacher of the Year award for the 2015-2016 academic school year for the UCCS College of Applied Science. At BYU, Dr. Harrison was voted the Most Influential Faculty Member in the Electrical and Computer Engineering Department for the 2022-2023 academic year, and he has taught courses in information theory, coding theory, machine learning, physical-layer security, stochastic processes, digital communications, digital signal processing, satellite communications, and signals and systems. He also serves actively in the broader electrical engineering community. Over the past six years, he has participated in fourteen workshops and conferences, many of which covered wireless security. He has served as a reviewer on five NSF proposal review panels, a “remote reviewer” for CHIST-ERA ERA-NET (a European consortium of twenty research funding organizations), and as a scholarly reviewer for multiple IEEE publications. His experience extends internationally, as he is fluent in Mandarin Chinese and for three years directed an NSF-funded International Research for Students (IRES) program in conjunction with the University of Coimbra, Portugal. Dr. Harrison’s primary expertise lies in coding theory, physical-layer security, probability and statistics, and digital communications. |
Date: Friday, November 7, 2025 Time: TBA Location: TBA Speaker: Robert Calderbank (Charles S. Sydnor Distinguished Professor at Duke University) Title: TBA Abstract: TBA Biography: Robert Calderbank is Director of the Information Initiative at Duke University, where he is Professor of Electrical Engineering, Computer Science and Mathematics. He joined Duke in 2010, completed a 3 year term as Dean of Natural Sciences in August 2013, and also served as Interim Director of the Duke Initiative in Innovation and Entrepreneurship in 2012. Before joining Duke he was Professor of Electrical Engineering and Mathematics at Princeton University where he also directed the Program in Applied and Computational Mathematics. Before joining Princeton University Dr. Calderbank was Vice President for Research at AT&T. As Vice President for Research he managed AT&T intellectual property, and he was responsible for licensing revenue. AT&T Labs was the first of a new type of research lab where masses of data generated by network services became a giant sandbox in which fundamental discoveries in information science became a source of commercial advantage At Duke, Dr. Calderbank works with researchers from the Duke Center for Autism and Brain Development, developing information technology that is able to capture a full spectrum of behavior in very young children. By supporting more consistent and cost-effective early diagnosis, the team is increasing the opportunity for early interventions that have proven very effective. At the start of his career at Bell Labs, Dr. Calderbank developed voiceband modem technology that was widely licensed and incorporated in over a billion devices. Voiceband means the signals are audible so these modems burped and squeaked as they connected to the internet. One of these products was the AT&T COMSPHERE® modem which was the fastest modem in the world in 1994 – at 33.6kb/s! Together with Peter Shor and colleagues at AT&T Labs Dr. Calderbank developed the group theoretic framework for quantum error correction. This framework changed the way physicists view quantum entanglement, and provided the foundation for fault tolerant quantum computation. Dr. Calderbank has also developed technology that improves the speed and reliability of wireless communication by correlating signals across several transmit antennas. Invented in 1996, this space-time coding technology has been incorporated in a broad range of 3G, 4G and 5G wireless standards. He served on the Technical Advisory Board of Flarion Technologies a wireless infrastructure company founded by Rajiv Laroia and acquired by Qualcomm for $1B in 2008. Dr. Calderbank is an IEEE Fellow and an AT&T Fellow, and he was elected to the National Academy of Engineering in 2005. He received the 2013 IEEE Hamming Medal for contributions to coding theory and communications and the 2015 Shannon Award. |
Date: Friday, November 14, 2025 Time: 2:00 pm Location: Seminar room EXP-310 Speaker: Muriel Medard (NEC Professor at MIT) Title: TBA Abstract: TBA Biography: Muriel Médard is the NEC Professor of Software Science and Engineering in the Electrical Engineering and Computer Science (EECS) Department at MIT, where she leads the Network Coding and Reliable Communications Group in the Research Laboratory for Electronics at MIT. She obtained three Bachelors degrees (EECS 1989, Mathematics 1989 and Humanities 1991), as well as her M.S. (1991) and Sc.D (1995), all from MIT. Muriel is a Member of the US National Academy of Engineering (elected 2020), a Member of the German National Academy of Sciences Leopoldina (elected 2022), a Fellow of the US National Academy of Inventors (elected 2018), American Academy of Arts and Sciences (elected 2021), and a Fellow of the Institute of Electrical and Electronics Engineers (elected 2008). She holds Honorary Doctorates from the Technical University of Munich (2020) and from The University of Aalborg (2022). Muriel was co-winner of the MIT 2004 Harold E. Egerton Faculty Achievement Award and was named a Gilbreth Lecturer by the US National Academy of Engineering in 2007. She received the 2017 IEEE Communications Society Edwin Howard Armstrong Achievement Award and the 2016 IEEE Vehicular Technology James Evans Avant Garde Award. Muriel was awarded the 2022 IEEE Kobayashi Computers and Communications Award. She received the 2019 Best Paper award for IEEE Transactions on Network Science and Engineering, the 2018 ACM SIGCOMM Test of Time Paper Award, the 2009 IEEE Communication Society and Information Theory Society Joint Paper Award, the 2009 William R. Bennett Prize in the Field of Communications Networking, the 2002 IEEE Leon K. Kirchmayer Prize Paper Award, as well as nine conference paper awards. Most of her prize papers are co-authored with students from her group. Muriel has served as technical program committee co-chair of ISIT (twice), CoNext, WiOpt, WCNC and of many workshops. She has chaired the IEEE Medals committee, and served as member and chair of many committees, including as inaugural chair of the Millie Dresselhaus Medal. She was Editor in Chief of the IEEE Journal on Selected Areas in Communications and has served as editor or guest editor of many IEEE publications, including the IEEE Transactions on Information Theory, the IEEE Journal of Lightwave Technology, and the IEEE Transactions on Information Forensics and Security. Muriel was a member of the inaugural steering committees for the IEEE Transactions on Network Science and for the IEEE Journal on Selected Areas in Information Theory. She currently serves as the Editor-in-Chief of the IEEE Transactions on Information Theory. Muriel was elected president of the IEEE Information Theory Society in 2012, and serves on its board of governors, having previously served for eleven years. Muriel received the inaugural 2013 MIT EECS Graduate Student Association Mentor Award, voted by the students. She set up the Women in the Information Theory Society (WithITS) and Information Theory Society Mentoring Program, for which she was recognized with the 2017 Aaron Wyner Distinguished Service Award. She served as undergraduate Faculty in Residence for seven years in two MIT dormitories (2002–2007). Murielwas elected by the faculty and served as member and later chair of the MIT Faculty Committee on Student Life and as inaugural chair of the MIT Faculty Committee on Campus Planning. She was chair of the Institute Committee on Student Life. She was recognized as a Siemens Outstanding Mentor (2004) for her work with High School students. She serves on the Board of Trustees since 2015 of the International School of Boston, for which she is treasurer. Muriel has over sixty US and international patents awarded, the vast majority of which have been licensed or acquired. For technology transfer, she has co-founded CodeOn, for which she consults, and Steinwurf, for which she is Chief Scientist. |
Past Talks in 2025
Date: Tuesday, September 16, 2025 (NU Calendar) Time: 3pm -4pm Location: Seminar room EXP-610 Speaker: Christian Grussler (Technion – Israel Institute of Technology, visiting MIT) Title: Variation Diminishing in Systems Theory and Sparse Optimization Abstract: Variation diminishment, i.e., the reducing of zero-crossings or local extrema is an elementary property that we expect from common tools in filtering, statistics, geometric modeling or approximation theory. Total positivity, the old and well-established theory behind this property, however, has barely entered the respected communities and been mostly forgotten by now. In this talk, we will shed new light on the importance of this property in system analysis such as the study of self-oscillations, as well as in approximation theory such as model order reduction and sparse optimization. Basic mathematical concepts and our recent theoretical extension of those will be reviewed based on graphical interpretations. This has been joint work with Prof. Rodolphe Sepulchre from KU Leuven, Dr. Thiago Burghi from the University of Cambridge, Prof. Tobias Damm from RPTU Kaiserslautern as well as my students Chaim Roth, Maya M. Marmary and Kang Tong from the Technion. Biography: Professor Grussler is currently an Assistant Professor at the Faculty of Mechanical Engineering, Technion – Israel Institute of Technology and a Jane and Larry Sherman Fellow. He conducts research that broadly intersects with the areas of Control Theory, Mathematical Optimization and Machine Learning. In particular, he is interested in the development of total positivity theory towards a unifying framework of these areas. Until January 2021, he was a Postdoctoral Scholar at the Department of Electrical Engineering and Computer Science, UC Berkeley, United States. Prior to that, he was a Research Associate with the control group at the Department of Engineering, University of Cambridge, United Kingdom as well as a postdoc and PhD student at the Department of Automatic Control, Lund University, Sweden. In his undergraduate studies, I was part of a double degree program between the University of Kaiserslautern and Lund University. He received an MSc in Engineering Mathematics from Lund University and a Dipl.-Math. techn. in Industrial Mathematics from the University of Kaiserslautern. |
Date: Monday, April 28th , 2025 (NU Calendar) Time: 11:00am-12:00pm Location: Seminar room EXP-310 (Remote meeting is available: Zoom link.) Speaker: James Gleeson (Professor of Industrial and Applied Mathematics, MACSI, University of Limerick, Ireland) Title: Branching-process models for information spread Abstract: I will review some mathematical models of the spreading of information, with the goal of describing certain observed dynamics of posting on online boards such as Reddit. Time is (mostly) considered as continuous, so self-exciting point processes such as the Hawkes process are relevant. We examine the classical branching process interpretation of the Hawkes process and then seek generalizations to model the diurnal variation in activity that is characteristic of online social media. Using a large dataset of over 10^8 posts from online opinion boards, we demonstrate the possible utility of a very simple model that provides an explanation (of sorts) for how the time of day at which content is posted can affect its eventual popularity, as quantified by the number of comments it attracts. This is joint work with Joseph O’Brien, Alberto Aleta and Yamir Moreno. Biography: Professor James Gleeson holds the Chair in Industrial and Applied Mathematics at the University of Limerick. He is a graduate of University College Dublin in Mathematical Sciences and Mathematical Physics and received his PhD in Applied Mathematics from Caltech in 1999. Following his graduation from Caltech, he was a visiting assistant professor in Arizona State University, and then moved to University College Cork for 7 years, before taking up his current position at the University of Limerick. He is an Associate Editor of the Journal of Complex Networks and a member of the editorial board of Physical Review E. He is the director of the SFI Centre for Research Training in Foundations of Data Science (www.data-science.ie), which will produce 130+ PhD graduates with industry-ready skills. As co-director of MACSI, the Mathematics Applications Consortium for Science and Industry, he leads research into applications of mathematics to real-world problems with significant economic and social impact. His research interests include stochastic dynamics and contagion on complex networks. |
Date: Tuesday, April 15th , 2025 (NU Calender) Time: 10:30 am- 11:30am Location: 509/511 Lake Hall Speaker: Robert Simon (London School of Economics and Political Science) Title: Proper graph colouring, optimization, and paradoxical decompositions Abstract: We show that there is an infinite graph of finite degree defined by a Borel equivalence relation on a probability space such that it can be coloured properly with 17 colours but only in ways that induce paradoxical decompositions. We show that there are problems of optimization such that every epsilon-optimal solution for small enough positive epsilon induces a paradoxical decomposition. Biography: Professor Simon an Associate Professor in the Department of Mathematics. Before this, he got an undergraduate degree in Political Science at Reed College, an M.Sc. in Mathematics at Ohio State University, a Ph.D. in Mathematics at Bielefeld (Germany) and an Habilitation in Mathematics at Goettingen (Germany). He did postdoctoral work at the Hebrew University. Research wise, he is part of the Analysis group. Much of his past work has been with various mathematical problems related to game theory. Today his main efforts concern the Banach Tarski Paradox, the existence of orbits in dynamical systems, and topological structures. He is interested in any good problem of mathematics and is willing to discuss any topic. |
| Special JOINT Meeting: Christopher King Memorial Meeting, April 12-13, 2025 The meeting will celebrate Chris’s life by focusing primarily on the areas of applied mathematics in which he made major contributions: Theoretical Physics; Applied Probability; and Stability Theory. Date: April 12-13, 2025 Location: EXP Room 610, 815 Columbus Ave, Boston, MA 02120 Schedule: https://chrisking.sites.northeastern.edu/schedule/ Conference overview: Held over two days in Northeastern University’s EXP building, the goal of the meeting is to provide a forum to celebrate Chris’s life and his life-long love of applied mathematics. Amongst other topics, Chris made significant contributions to: Quantum Information Theory; Computer Networking; Smart Cities; and the mathematical analysis of Distributed Ledgers. |