Northeastern University, Department of Mathematics
Organizers: Ken Duffy, Eugene Tang, He Wang
*For remote/hybrid meetings, Zoom link will be sent by email upon request. Contact Eugene Tang at e.tang@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 Eugene Tang.
Note: The time and location of the seminar are not fixed!
Upcoming Talks
| Date: Time: Location: Speaker: Title: Abstract: Biography: |
Past Talks in 2025
| Date: Friday, November 14, 2025 (NU Calendar) Time: 2:00 pm Location: Seminar room EXP-310 (Microsoft Teams meeting is also available here) Speaker: Muriel Medard (NEC Professor at MIT)  Title: Building the Fastest Decentralized Internet Protocol for Web3 Abstract: Traditional computing follows the von Neumann architecture, where a compute/control unit interacts with read/write memory via a bus. Compute/control relies crucially on memory and access to it. This model has underpinned decades of innovation. Web3 has traditionally developed technologies such as virtual machines (VMs), that map onto von Neumann’s compute/control framework. Data propagation (bus) and access (read/write memory), however, have emerged as present critical constraints in decentralized environments. Central to Web3 is the data propagation aspect, where data is shared among validators to achieve consensus, or captured by block builders to create valuable blocks. We introduce the use network coding for data propagation (MumP2P) by leveraging Random Linear Network Coding (RLNC). We show how, through simple mean-field approaches, we can derive the order optimality of RLNC in data propagation. 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. Muriel obtained three Bachelor’s degrees (EECS 1989, Mathematics 1989 and Humanities 1991), as well as her M.S. (1991) and Sc.D (1995), all from MIT. She is a Member of the German National Academy of Sciences Leopoldina (elected 2022), the American Academy of Arts and Sciences (elected 2021), the US National Academy of Engineering (elected 2020), a Fellow of the Royal Academy of Engineering (elected 2025), a Fellow of the US National Academy of Inventors (elected 2018), and a Fellow of the Institute of Electrical and Electronics Engineers (elected 2008). Muriel worked as an advisor on the National Science Foundation’s Computer and Informational Science and Engineering (CISE) Advisory committee from 2020 to 2024, as well as a chair of the IEEE Koji Kobayashi Computers and Communications Award Committee from 2023 to the present. She holds Honorary Doctorates from the Technical University of Munich (2020), from The University of Aalborg (2022), and from the Budapest Institute of Technology and Economics (BME) (2023). Muriel was co-winner of the MIT 2004 Harold E. Edgerton 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 a 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 served 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 served on its board of governors for a dozen years Muriel received the inaugural MIT Excellence in Postdoctoral Mentoring Award (2022) and in 2013 the inaugural MIT EECS Graduate Student Association Mentor Award, voted by the students. She was recognized nationally as a Siemens Outstanding Mentor (2004) for her work with High School 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 IEEE Aaron Wyner Distinguished Service Award. She served as an undergraduate Faculty in Residence for seven years in two MIT dormitories (2002–2007). Muriel was elected by the faculty and served as a member and later chair of the MIT Faculty Committee on Student Life and as the inaugural chair of the MIT Faculty Committee on Campus Planning. She was chair of the Institute Committee on Student Life. She served on the Board of Trustees of the International School of Boston from 2015 to 2024, for which she was treasurer. She serves on the Nokia Bell Labs Technical Advisory Board. Muriel has over eighty US and international patents awarded, the vast majority of which have been licensed or acquired. For technology transfer, she has co-founded Nanoping and CodeOn, for which she consults. Most recently, she co-founded Optimum where she serves as CEO. Muriel has supervised over 40 master’s students, over 25 doctoral students and over 30 postdoctoral fellows. |
| Date: Friday, November 7, 2025 (NU Calendar) Time: 2:00 pm Location: EXP-610A Seminar Room (Microsoft Teams meeting is also available here.) Speaker: Robert Calderbank (Professor at Duke University, Charles S. Sydnor Distinguished Professor)  Title: Does 6G Wireless Need a New Waveform Abstract: Every new generation is an opportunity to reflect on fundamentals of wireless communication, and when we adopt new technology we calculate that the benefits of switching justify pain of transition. We introduced multiple antennas in 3G to satisfy demand for high speed data, and we introduced OFDMA in 4G to make a direct wireless connection to the internet. In 6G we anticipate that engineering focus will shift from the downlink to the uplink as users become significant sources of data. We anticipate new applications that integrate sensing and communication, also that AI/ML will start to transform transceiver processing. In this talk we describe how to enable 6G applications using a carrier waveform that is a pulse in the delay-Doppler domain. Brief Biography: Dr. Calderbank is known for contributions to voiceband modem technology, to quantum information theory, and for co-invention of space-time codes for wireless communication. His research papers have been cited more than 60,000 times, and his inventions are found in billions of consumer devices. Dr. Calderbank was elected to the National Academy of Engineering in 2005, to the National Academy of Inventors in 2015, and to the American Academy of Arts and Sciences in 2022. He has received a number of awards, including the 2013 IEEE Hamming Medal for contributions to information transmission, and the 2015 Claude E. Shannon Award. |
Date: Thursday, October 16, 2025 (NU Calendar) Time: 2:00 pm Location: Seminar room EXP-701A Speaker: Willie Harrison (Brigham Young University) Title: Applications of Vector Spaces in Wiretap Code Constructions Abstract: Physical-layer security seeks to achieve secure throughput by exploiting the statistics of the noisy transmission channel to an eavesdropper. In practice, this requires knowledge of the environment coupled with clever application of wiretap codes. These codes are one-to-many mappings, where single messages are mapped to any of several codewords at random. The sets of codewords that are assigned to a single message are cosets of a vector space. This talk presents techniques for optimizing the design of the vector space (and, consequently, the cosets) for best-possible wiretap codes. We show that for small parameters, the best codes tend to be old codes. Biography: Dr. Willie Harrison received his BS/MS degrees from Utah State University in 2007, and his PhD from the Georgia Institute of Technology in 2012. He was an assistant professor at the University of Colorado at Colorado Springs from 2012-2017, and he joined the faculty in the Department of Electrical and Computer Engineering at Brigham Young University in the fall of 2017, where he is currently an Associate Professor. His research interests are in physical-layer security, wiretap code design, post-quantum cryptography, error-control coding, author identification, and sports analytics. |
Date: Thursday, October 9, 2025 Time: 2:00 pm Location: Seminar room EXP-610 (NU Calendar) 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: 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. |