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Fall 2025
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Elizabeth Gillaspy – 91次元
Zappa-Szép products and Higher-Rank Graphs
Zappa-Szép products are a generalization of a semidirect product, in which two groups act on each other compatibly to form a new group. In recent years, the notion of Zappa-Szép product has been extended from groups to a wide variety of mathematical structures, including the higher-rank graphs which are the focus of my research. In 2021, a summer research team consisting of UM students Adlin Abell-Ball, George Glidden-Handgis, and S. Joseph Lippert discovered a new Zappa-Szép like structure for higher-rank graphs, which does not quite coincide with the existing definition in the literature. In this talk, I'll tell you about their work, and how it sheds new light on the structure of higher-rank graphs.
September 15, 2025 at 3:00 p.m. Math 103
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Dan Finkel – Math for Love, Early Family Math
Anatomy of a Beautiful Math Experience
What makes a mathematical experience inspiring or empowering instead of tedious or miserable? In this presentation, we'll explore why people love and hate math, and how to create opportunities for meaningful mathematical learning.
About the Speaker
Dan Finkel is a game creator, curriculum writer, puzzle author, and math evangelist. He gives talks nationally and internationally, and his TEDx Talk - - has been viewed over a million times. Dan’s Math for Love curriculum has been used by thousands of students, and is known for its combination of rigor and play. The math games he created with his wife, Katherine Cook, have won over 30 awards. They include Prime Climb, Tiny Polka Dot, Multiplication by Heart, and Rolly Poly. Dan is also the author of Pattern Breakers, a playful book of patterns for young children. Dan is the Founder of , a Seattle-based organization devoted to transforming how math is taught and learned. Dan is also Cofounder of , which provides free, quality math resources for children from birth to 8.
October 15, 2025 at 3:00 p.m. Math 103
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Faculty Evaluation Committee meeting
October 27, 2025 at 3:00 p.m. Math 103
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Jason DeBlois – University of Pittsburgh
Things we know, and things we do not, about knots.
In this talk, by knots I will mean circles embedded in three-dimensional space. I’ll start with background and some history, spend some time on knot invariants, then turn to the geometric perspective on knot complements that was introduced by Thurston around 1980. Along the way, I’ll mention some significant open questions in the subject. I’ll finish by discussing recent progress on a couple of geometric questions, on hidden symmetries of and totally geodesic surfaces in hyperbolic knot complements.
November 3, 2025 at 3:00 p.m. Math 103
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Javi Pérez-Álvaro – 91次元
November 10, 2025 at 3:00 p.m. Math 103
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Junwei Liao – 91次元
November 24, 2025 at 3:00 p.m. Math 103
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Eric Marland – Appalachian State University & the 91次元
The -ing of Mathematical Modeling
December 1, 2025 at 3:00 p.m. Math 103
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WiSEN research team – Researchers from WSU, Gonzaga U, UI, Rochester Institute of Tech and UM
March 9, 2026 at 3:00 p.m. Math 103
Available Dates for Fall 2025
October 20
November 17
Spring 2025
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Shira Gilat – University of Pennsylvania
The Algebra of Supernatural Matrices
The algebra of supernatural matrices is a key example in the theory of locally finite central simple algebras. Supernatural matrices are a minimal solution to the equation of unital algebras Mn(X) ∼= X, which we compare to several similar conditions involving cancellation of matrices. This algebra has appeared under various names before, and it generalizes both McCrimmon's deep matrices algebra and m-petal Leavitt path algebra.
March 10, 2025 at 3:00 p.m. Math 103
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Christian López Mercado – 91次元, PhD Candidate
Reinventing Difficult Concepts in Advanced Mathematics
Many students struggle with abstract mathematical structures and concepts due to their highly formal nature and lack of intuitive entry points. In this talk, I explore how we can leverage the Realistic Mathematics Education (RME) framework to help students reinvent difficult concepts in number theory and abstract algebra. Through carefully designed instructional sequences, students work together to reinvent the concept of a group in abstract algebra and promote the learning of primitive roots in number theory, perhaps making these concepts more accessible and meaningful. Attendees will gain insights into practical strategies for implementing RME in advanced mathematics courses, ultimately bridging the gap between intuition and formal mathematical abstraction.
March 31, 2025 at 3:00 p.m. Math 103
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Nhan Nguyen – Amazon Web Services
Prompt-Tuned Multi-Task Taxonomic Transformer (PTMTTaxoFormer)
Hierarchical Text Classification (HTC) is a subclass of multi-label classification, it is challenging because the hierarchy typically has a large number of diverse topics. Existing methods for HTC fall within two categories, local methods (a classifier for each level, node, or parent) or global methods (a single classifier for everything). Local methods are computationally expensive, whereas global methods often require complex explicit injection of the hierarchy, verbalizers, and/or prompt engineering. In this work, we propose Prompt Tuned Multi Task Taxonomic Transformer, a single classifier that uses a multi-task objective to predict one or more topics. The approach is capable of understanding the hierarchy during training without explicit injection, complex heads, verbalizers, or prompt engineering. PTMTTaxoFormer is a novel model architecture and training paradigm using differentiable prompts and labels that are learnt through backpropagation. PTMTTaxoFormer achieves state of the art results on several HTC benchmarks that span a range of topics consistently. Compared to most other HTC models, it has a simpler yet effective architecture, making it more production-friendly in terms of latency requirements (a factor of 2-5 lower latency). It is also robust and label-efficient, outperforming other models with 15\%-50\% less training data.
April 14, 2025 at 3:00 p.m. Math 103
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Eric Chesebro – 91次元
Kleinian groups: history and recent results
Kleinian groups, first studied by Felix Klein and Henri Poincaré in the late 19th century, are discrete groups of isometries of hyperbolic 3-space. Since then, they’ve become central objects in mathematics, with deep connections to fields including number theory, complex analysis, and geometric topology.
In this talk, I’ll share some of the historical development of Kleinian groups and aim to give a sense of what they are and why they matter. Along the way, I’ll highlight some examples and explain how these groups arise naturally in geometry and low-dimensional topology. I'll finish with more recent results and share connections to problems I worked on during my sabbatical in Australia and New Zealand.April 28, 2025 at 3:00 p.m. Math 103
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