MAAGC at VCU 

The 2026 edition of the Mid-Atlantic Algebra, Geometry, and Combinatorics (MAAGC) Workshop will take place from Friday to Sunday, October 23-25, 2026, at Virginia Commonwealth University (VCU) in Richmond, VA.

The MAAGC Workshop aims to bring together senior researchers and junior mathematicians from the region to exchange ideas and forge collaborations in algebra, geometry, and combinatorics. The conference is funded by National Science Foundation grant DMS-2408985.

Speakers

Sergi Elizalde (Dartmouth College)

Leonardo Mihalcea (Virginia Tech)

Rebecca R.G. (George Mason University)

Brendon Rhoades (University of California, San Diego)

Josef Svoboda (Caltech)

Bridget Tenner (DePaul University)

Martha Yip (University of Kentucky)

Panel discussion on Effective Mathematical Writing

Ashvin Swaminathan (Harvard University and Axiom Math)

Ken Ono (University of Virginia and Axiom Math)

Bridget Tenner (DePaul University)

Will Traves (United States Naval Academy) - *TBC

Martha Yip (University of Kentucky)

Organizers

Joel B Lewis (The George Washington University)

Anna Pun (CUNY-Baruch College)

Nicola Tarasca (Virginia Commonwealth University)

Location

The conference will be held on the VCU Monroe Park campus in Richmond, VA.

Participants are expected to arrange their own accommodation unless contacted by the organizers. Several hotels are located within walking distance of the conference venue. We encourage participants to book their accommodation well in advance.

Schedule

Friday

3:15pm – 3:30am: Check in

3:30pm – 4:30pm: Rebecca R.G.

5:30pm – 6:30pm: Brendon Rhoades

Saturday

10:00am – 11:00am: Leonardo Mihalcea

12:00pm – 1:00pm: Josef Svoboda

1:00pm – 2:30pm: Lunch Break

2:30pm – 3:30pm: Panel

3:45pm – 5:45pm: Poster session 

Sunday

10:00am – 11:00am: Sergi Elizalde

11:30am – 12:30pm: Bridger Tenner

1:00pm – 2:00pm: Martha Yip

Abstracts

Sergi Elizalde: Cylindric growth diagrams, walks in simplices, and exclusion processes

We establish bijections between three classes of combinatorial objects that have been studied in different contexts: lattice walks in simplicial regions as introduced by Mortimer--Prellberg, standard cylindric tableaux as introduced by Gessel--Krattenthaler and Postnikov, and sequences of states in the totally asymmetric simple exclusion process on a cycle. This perspective allows us to translate symmetries from one setting into another, revealing unexpected properties of these objects.

Specifically, we show that a recent bijection of Courtiel et al. between certain simplicial walks with forward and backward steps is equivalent to a cylindric analogue of the Robinson--Schensted correspondence. Originally defined by Neyman by iterating an insertion operation, we provide an alternative description of this correspondence by introducing a cylindric version of Fomin's growth diagrams. This natural description elucidates the symmetry of the correspondence, and it allows us to interpret the above walks as oscillating cylindric tableaux.

Leonardo Mihalcea: Quantum Schubert Calculus from lattice models

Quantum Schubert Calculus arises from questions in Enumerative Geometry, such as how many rational curves of a specified degree intersect general translates of Schubert varieties in a Grassmannian. The answer may be found by calculating the structure constants of the multiplication of Schubert classes in an appropriate quantum intersection ring associated to a Grassmann manifold. I will explain how techniques from statistical mechanics, namely the combinatorics of partition functions of certain lattice models, yield explicit combinatorial formulae for the Schubert structure constants. Joint work with V. Gorbounov and C. Korff.

Rebecca R.G.: Applications of algebra, geometry, and combinatorics to spatial navigation

There are three types of cells involved in spatial navigation: place cells, grid cells, and head direction cells. Place cells fire every time an animal is in a specific location, grid cells fire in a repeating sequence as the animal travels along particular trajectories, and head direction cells indicate the way an animal is facing. While many people study these using mathematical modeling and more traditional applied mathematics techniques, there is a growing community of people using algebraic, geometric, and combinatorial tools to analyze place and grid cells. In this talk I'll discuss how I use combinatorial commutative algebra to study place cells (building on work of Curto, Itskov, et al) and geometry to study grid cells. The work on place cells is joint with Hugh Geller, Alexandra Seceleanu, and Nora Youngs, and the work on grid cells is joint with Giorgio Ascoli, Holger Dannenberg, Kelsi Listman, Nate Sutton, and Anthony Vu.

Brendon Rhoades: Coinvariants, hyperplanes, and superspace

Let V be a finite-dimension vector space. The superspace ring associated to V is the tensor product \Omega of the ring S of polynomial functions on V with the exterior algebra E over V. If G is any subgroup of GL(V), there is a natural bigraded action of G on \Omega, and the superspace coinvariant ring SR_G is obtained by quotienting \Omega by the ideal generated by G-invariants with vanishing constant term. We study the structure of SR_G when G is a complex reflection group and V is its reflection representation with a special focus on type A. The theory of hyperplane arrangements plays an important role. Joint with Robert Anarone, Sutanay Bhattacharya, Patty Commins, Trevor Karn, Satoshi Murai, and Andy Wilson.

Josef Svoboda: Brieskorn homology 3-spheres, GL(2,Z) and the Stern—Brocot tree

The d-invariant of a homology sphere $\Sigma(p,q,r)$ is a non-negative integer. It obstructs the existence of smooth contractible 4-manifolds with the boundary $\Sigma(p,q,r)$.  By a result of Elkies, d vanishes exactly when the corresponding resolution (or plumbing) lattice is diagonalizable. We completely characterize Brieskorn spheres $Sigma(2,q,r)$ with d=0, using the combinatorics of Stern—Brocot tree and free submonoids of GL(2,Z). Joint work with Shimal Harichurn, Isabella Khan and András Némethi.

Bridget Tenner: Permutation Patterns: TNG

Permutations are a classic tool for modeling a variety of scenarios. The study of permutations in their own right, as combinatorial objects, has blossomed in the last half century through a burgeoning interest in permutation patterns. The patterns that a given permutation contains (or avoids) have shown remarkable relevance - and with applications to numerous other fields. We will discuss major themes of that research, as well as exciting and relatively new directions for the field. These directions, sometimes complementary to classical results, have already shown great utility and are poised for even more, suggesting a thrilling new generation of research to come. Including collaborations with Yosef Berman, Ian Cavey & Hugh Dennin, Joel Lewis, and Kyle Petersen

Martha Yip: Flag positroid pipe dreams

We introduce flag positroid pipe dreams (FPPs), whose role in the study of complete flag positroids is analogous to the role of Le-diagrams in the study of positroids. FPPs are in bijection with intervals in the Bruhat order and hence index Richardson cells in the decomposition of the nonnegative flag variety. In this talk, we will show how a flag positroid can be built rank by rank via FPPs, and conversely given an FPP, how to recover the constituents of its associated complete flag positroid in terms of their Le-diagrams. As an application, we address a problem posed by Chen et al. regarding a characterization of elementary positroid quotients via the cyclic shift operators of Benedetti et al.

Poster session

TBA

Registration

Please register here. Registration is free, but helpful for planning purposes (space and refreshments). Junior participants (undergraduate and graduate students as well as postdocs) are encouraged to participate in the poster session. Please include a tentative poster title during registration if you wish to be considered. 

Financial support

There is funding for travel and accommodation, especially for early-career participants presenting at the poster session. Register by September 23 to receive full consideration for funding. Please contact the organizers as soon as possible if childcare is requested.