All Lectures took place in the main lecture hall of the IC building (HIC). Video recordings of the lectures are available on our YouTube page.
| Sunday | Monday | Tuesday | Wednesday | Thursday | Friday | |
|---|---|---|---|---|---|---|
| 8:00 | Registration | |||||
| 8:45 | Opening Remarks | |||||
| 9:00 | Josephine Yu | Rosa Orellana | Kris Shaw | Markus Reineke | Nicholas Proudfoot | |
| 9:30 | ||||||
| 10:00 | Changxin Ding | Damián de la Fuente | Philippe Nadeau | Matteo Parisi | Nicolle Gonzalez | |
| 10:30 | Coffee Break | |||||
| 11:00 | Leo Jiang | Tianyi Yu | Wenjie Fang | Florian Schreier-Aigner | Christin Bibby | |
| 11:30 | Jeanne Scott | Christian Gaetz | Greta Panova | Ricky Liu | Shuhei Tsujie | |
| 12:00 | Lunch | Lunch | Conference Photo | FPSAC 2025 | Lunch | |
| 12:30 | Lunch | Lunch | ||||
| 13:00 | ||||||
| 13:30 | Excursions | |||||
| 14:00 | Carolina Benedetti | Satoshi Murai | Lisa Sauermann | Michael Joswig | ||
| 14:30 | ||||||
| 15:00 | Steven Karp | Eva Philippe | Zhongyang Li | Anastasia Nathanson | ||
| 15:30 | Coffee Break | Coffee Break | ||||
| 16:00 | Patricia Commins | Matias von Bell | Pierre Bonnet | Jonah Berggren | ||
| 16:30 | Gaku Liu | Vincent Pilaud | Valentin Feray | Nathan Williams | ||
| 17:00 | Welcome Reception | Arun Ram | Poster Session 1 | Poster Session 2 | Closing Remarks | |
| 17:30 | Ice Cream Social | |||||
| 18:00 | ||||||
| 18:30 | Banquet | |||||
| 19:00 | ||||||
| 19:30 | ||||||
| Time | Speaker | Notes |
|---|---|---|
| 17:00 – 20:00 | Welcome Reception | at the mensa ( = dining hall) |
Lectures take place in the main lecture hall of the IC building (HIC).
| Time | Speaker | Notes |
|---|---|---|
| 8:00 – 8:45 | Registration | in HIC |
| 8:45 – 9:00 | Opening Remarks | in HIC |
| 9:00 – 10:00 | Josephine Yu Real Tropical Geometry, Determinants, and Matroidal Structures |
Abstract, Slides |
| 10:00 – 10:30 | Changxin Ding A framework unifying some bijections for graphs and its connection to Lawrence polytopes |
Extended Abstract, Slides, Video Recording |
| 10:30 – 11:00 | Coffee Break | in ID 04/459 and ID 04/471 |
| 11:00 – 11:30 | Leo Jiang Real matroid Schubert varieties, zonotopes, and virtual Weyl groups |
Extended Abstract, Slides |
| 11:30 – 12:00 | Jeanne Scott Diagram model for the Okada algebra and monoid |
Extended Abstract, Slides, Video Recording |
| 12:00 –14:00 | Lunch | |
| 14:00 – 15:00 | Carolina Benedetti On flags of positroids: enumerative and geometric aspects via lattice path matroids |
Abstract, Slides |
| 15:00 – 15:30 | Steven Karp Universal Pluecker coordinates for the Wronski map and positivity in real Schubert calculus |
Extended Abstract, Slides |
| 15:30 – 16:00 | Coffee Break | in ID 04/459 and ID 04/471 |
| 16:00 – 16:30 | Patricia Commins Invariant theory for the face algebra of the braid arrangement |
Extended Abstract, Slides, Video Recording |
| 16:30 – 17:00 | Gaku Liu A regular unimodular triangulation of the matroid base polytope |
Extended Abstract, Slides, Video Recording |
| 17:00 – 18:00 | Arun Ram Ian G. Macdonald: Works of Art |
Abstract, Slides, Video Recording |
Lectures take place in the main lecture hall of the IC building (HIC).
| Time | Speaker | Notes |
|---|---|---|
| 9:00 – 10:00 | Rosa Orellana See-Saw Pairs and Plethysm |
Abstract, Slides |
| 10:00 – 10:30 | Damián de la Fuente On the size of Bruhat intervals |
Extended Abstract, Slides, Video Recording |
| 10:30 – 11:00 | Coffee Break | in ID 04/459 and ID 04/471 |
| 11:00 – 11:30 | Tianyi Yu Analogues of two classical pipedream results on bumpless pipedreams |
Extended Abstract, Slides, Video Recording |
| 11:30 – 12:00 | Christian Gaetz Pattern heights and the minimal power of \(q\) in a Kazhdan–Lusztig polynomial |
Extended Abstract, Slides, Video Recording |
| 12:00 –14:00 | Lunch | |
| 14:00 – 15:00 | Satoshi Murai Stanley-Reisner rings and triangulated manifolds |
Abstract, Slides |
| 15:00 – 15:30 | Eva Philippe Realizing the \(s\)-permutahedron via flow polytopes |
Extended Abstract, Slides, Video Recording |
| 15:30 – 16:00 | Coffee Break | in ID 04/459 and ID 04/471 |
| 16:00 – 16:30 | Matias von Bell Framing lattices and flow polytopes |
Extended Abstract, Slides |
| 16:30 – 17:00 | Vincent Pilaud Acyclonestohedra |
Extended Abstract, Slides, Video Recording |
| 17:00 – 18:30 | Poster Session 1 | in the coffee break area |
Lectures take place in the main lecture hall of the IC building (HIC).
| Time | Speaker | Notes |
|---|---|---|
| 9:00 – 10:00 | Kris Shaw Patchworking in higher codimension and oriented matroids |
Abstract, Slides |
| 10:00 – 10:30 | Philippe Nadeau Smirnov words and the Delta conjectures |
Extended Abstract, Slides, Video Recording |
| 10:30 – 11:00 | Coffee Break | in ID 04/459 and ID 04/471 |
| 11:00 – 11:30 | Wenjie Fang Tamari intervals and blossoming trees |
Extended Abstract, Slides, Video Recording |
| 11:30 – 12:00 | Greta Panova All Kronecker coefficients are reduced Kronecker coefficients |
Extended Abstract, Slides, Video Recording |
| 12:00 –12:30 | Conference Photo | |
| 12:30 – 13:00 | Lunch | |
| 13:00 – 20:00 | Excursions |
Lectures take place in the main lecture hall of the IC building (HIC).
| Time | Speaker | Notes |
|---|---|---|
| 9:00 – 10:00 | Markus Reineke Motivic generating series of quiver representations |
Abstract, Video Recording |
| 10:00 – 10:30 | Matteo Parisi Cluster algebras and tilings for the \(m=4\) amplituhedron |
Extended Abstract, Slides |
| 10:30 – 11:00 | Coffee Break | in ID 04/459 and ID 04/471 |
| 11:00 – 11:30 | Florian Schreier-Aigner \(qtRSK^∗\): A probabilistic dual RSK correspondence for Macdonald polynomials |
Extended Abstract, Slides |
| 11:30 – 12:00 | Ricky Liu Plane partitions and rowmotion on rectangular and trapezoidal posets |
Extended Abstract, Slides, Video Recording |
| 12:00 – 12:30 | FPSAC 2025 Announcement | Slides, Website |
| 12:30 – 14:00 | Lunch | |
| 14:00 – 15:00 | Lisa Sauermann The Erdős–Ginzburg–Ziv Problem in Discrete Geometry |
Abstract, Slides |
| 15:00 – 15:30 | Zhongyang Li Asymptotics of Bounded Lecture-Hall Tableaux |
Extended Abstract, Slides, Video Recording |
| 15:30 – 16:00 | Coffee Break | in ID 04/459 and ID 04/471 |
| 16:00 – 16:30 | Pierre Bonnet A Galois structure on the orbit of walks in the quadrant |
Extended Abstract, Slides |
| 16:30 – 17:00 | Valentin Feray A determinantal point process approach to scaling and local limits of random Young tableaux |
Extended Abstract, Slides, Video Recording |
| 17:00 – 18:30 | Poster Session 2 | in the coffee break area |
| 18:30 | Banquet | at the mensa ( = dining hall), drinks start at 18:30, food starts at 19:15 |
Lectures take place in the main lecture hall of the IC building (HIC).
| Time | Speaker | Notes |
|---|---|---|
| 9:00 – 10:00 | Nicholas Proudfoot Categorical valuations for polytopes and matroids |
Abstract, Slides (without pauses), Slides (with pauses), Video Recording |
| 10:00 – 10:30 | Nicolle Gonzalez Triangular \((q, t)\)-Schroder Polynomials and Khovanov-Rozansky Homology |
Extended Abstract, Slides |
| 10:30 – 11:00 | Coffee Break | in ID 04/459 and ID 04/471 |
| 11:00 – 11:30 | Christin Bibby Supersolvable posets and fiber-type arrangements |
Extended Abstract, Slides |
| 11:30 – 12:00 | Shuhei Tsujie The characteristic quasi-polynomials for exceptional well-generated complex reflection groups |
Extended Abstract, Slides |
| 12:00 – 14:00 | Lunch | |
| 14:00 – 15:00 | Michael Joswig Hypersimplices, tropical geometry and finite metric spaces |
Abstract, Slides, Video Recording |
| 15:00 – 15:30 | Anastasia Nathanson Chow rings of matroids as permutation representations |
Extended Abstract, Slides, Video Recording |
| 15:30 – 16:00 | Coffee Break | in ID 04/459 and ID 04/471 |
| 16:00 – 16:30 | Jonah Berggren Wilting Theory of Flow Polytopes |
Extended Abstract, Slides, Video Recording |
| 16:30 – 17:00 | Nathan Williams Charmed roots and the Kroweras complement |
Extended Abstract, Animated Slides (Note: these slides may not work on mobile devices!), Video Recording |
| 17:00 – 17:30 | Closing Remarks | |
| 17:30 – 19:00 | Ice Cream Social |
Title: On flags of positroids: enumerative and geometric aspects via lattice path matroids
Abstract: Positroids are a family of representable matroids that have gain lots of attention in enumerative and algebraic combinatorics, in tropical geometry and in physics. Lattice path matroids (LPMs) are a subclass of positroids that are very well behaved. In particular, LPMs provide (regular) subdivisons of the uniform matroid \(U_{k,n}\). Subdivisions of \(U_{k,n}\) into positroids have been studied in the last years by various authors, in the context of nonnegativity in tropical geometry. On the other hand, the permutahedron \(P_n\) can be thought as the flag matroid whose constituents are \(U_{1,n}, U_{2,n},...,U_{n,n}\). Subdivisions of \(P_n\) into flags of positroids appear in recent work of several authors, in the context of the nonnegative tropical flag variety. In this talk we will explore flags of positroids focusing on flags of LPMs, as well as subdivisions of \(P_n\) into LPMs and will interpret these results in various contexts. This is current work with K. Knauer.
Title: Hypersimplices, tropical geometry and finite metric spaces
Abstract: The hypersimplex \(\Delta(k,n)\) is the convex polytope which is the set of those points in the unit cube \([0,1]^n\) which satisfy the affine linear equation \(\sum x_i=k\). We report on known and new results concerning the secondary fan \(\Sigma(k, n)\), which stratifies the regular subdivisions of \(\Delta(k,n)\). For tropical geometry this is relevant because \(\Sigma(k,n)\) contains the tropical Grassmannian \({\rm TGr}(k,n)\) as a subset; we discuss that relationship. Furthermore, in the special case \(k = 2\) the fan \(\Sigma(2,n)\) is closely related to the metric fan \({\rm MF}(n)\), which forms a natural parameter space for the metric spaces on \(n\) points. Our analysis of the fans \(\Sigma(2,n)\) improves known results of Bandelt and Dress concerning structural properties of finite metric spaces, with applications to phylogenetics. The new results are joint work with Laura Casabella and Lars Kastner.
Title: Stanley-Reisner rings and triangulated manifolds
Abstract: Applications of Stanley-Reisner rings to combinatorics of simplicial complexes is classical in algebraic combinatorics. In particular, this approach has yield various important combinatorial results on simplicial polytopes and triangulated spheres since their Stanley-Reisner rings have nice algebraic properties. In the last 15 years, it has been found that classical results on Stanley–Reisner rings of polytopes and spheres can be naturally generalized to triangulated manifolds, and these generalizations have been applied to study combinatorial properties of triangulated manifolds. In this talk, I will show key algebraic results on this topic and explain how these algebraic results are applied to study combinatorics of triangulated manifolds.
Title: See-Saw Pairs and Plethysm
Abstract: The Plethysm problem asks for a combinatorial interpretation of the coefficients which occur in the composition of two polynomial representations of the general group. Making progress even for special cases has proven to be extremely difficult. The plethysm coefficients occur in many other problems in algebraic combinatorics such as the restriction problem, which asks for a combinatorial interpretation to the coefficient occurring when a polynomial representation of the general linear group is restricted to the symmetric group (realized as permutation matrices). Other problems related to plethysm are finding symmetric chain decompositions for the truncated Young lattice and Foulkes’ conjecture.
In this talk I will describe how the representation theory of diagram algebras gives another interpretation to the plethysm problem. The connection to diagram algebras is achieved using see-saw pairs and centralizer algebras which uses the representation theory of a subalgebra of uniform block permutations of the partition algebra. This leads to a new approach to an important special case of the plethysm problem which would lead to solutions to the restriction, symmetric chain decomposition problem, and Foulkes’ conjecture. This is joint work with F. Saliola, A. Schilling, and M. Zabrocki.
Title: Categorical valuations for polytopes and matroids
Abstract: A polytope valuation is an invariant that is additive under decompositions of polytopes into smaller polytopes. A matroid valuation is similar, with a focus on base polytopes of matroids. This property is extremely useful for calculations and also surprisingly common. I will describe a way to categorify the notion of a valuation, with two goals in mind. The first is to provide a more satisfying explanation for why certain invariants are valuations. The second is to perform richer calculations that take into account the actions of symmetry groups of polytopes or matroids.
Slides (without pauses), Slides (with pauses)
Title: Motivic generating series of quiver representations
Abstract: We introduce generating series “counting” representations of quivers and discuss structural properties such as product factorizations and functional equations, and their relation to algebraic combinatorics and moduli spaces.
Title: The Erdős–Ginzburg–Ziv Problem in Discrete Geometry
Abstract: The Erdős–Ginzburg–Ziv Problem is a classical extremal problem in discrete geometry. For given positive integers \(m\) and \(n\), it asks the following question: What is the minimum number \(s\) such that among any \(s\) points in the \(n\)-dimensional integer lattice \(\mathbb{Z}^n\) there are always \(m\) points whose centroid is also a lattice point? It turns out that it essentially suffices to consider the case where \(m=p\) is a prime number, and that the problem then naturally translates into a problem over the finite field \(\mathbb{F}_p\). A wide range of different algebraic techniques can be used to approach this problem in different ranges for \(p\) and \(n\). This talk will give an overview of the known bounds for the problem, and of the different techniques that were used to obtain them. A particular focus of the talk will be the case where \(m=p\) is a fixed prime and \(n\) is large with respect to \(p\).
Title: Patchworking in higher codimension and oriented matroids
Abstract: The Ardila-Klivans fan of a matroid provides a direct link between matroids and toric/tropical geometry and has had impressive applications in recent years. In this talk, I will provide a cryptomorphic description of a matroid orientation, known as a real phase structure. Via a generalisation of Viro’s patchworking procedure this provides a link between oriented matroids and real toric varieties and even a homological obstruction to matroid orientation.
Real phase structures are also obtained when tropicalising a real algebraic variety. When the tropicalisation is locally matroidal, I will explain how the tropicalisation together with the real phase structure can be used to recover the topology of a real algebraic variety near the tropical limit. Finally, the topology of these real algebraic varieties, and more general patchworks, can be studied by adapting a spectral sequence from the case of hypersurfaces. This spectral sequence arises from filtrations of the tope space of an oriented matroid.
This talk is based in part on joint work with Allermann & Rau and Yuen.
Title: Real Tropical Geometry, Determinants, and Matroidal Structures
Abstract: I will discuss how tropical geometry reveals matroidal structures in certain real algebraic geometric objects. Brändén showed in 2010 that tropicalization of stable polynomials, including some determinantal polynomials arising from positive semidefinite matrices, exhibit M-convexity introduced by Murota (M stands for matroids). Brändén’s result was later extended to Lorentzian polynomials and positively hyperbolic varieties. I will provide an overview of tropicalization, survey these results, and present our new joint work with Abeer Al Ahmadieh, Felipe Rincón, and Cynthia Vinzant on studying the tropicalization of principal minors of positive semidefinite matrices using M-convexity, tropical Grassmannians, and tropical flag varieties.
Title: Ian G. Macdonald: Works of Art
Speaker: Arun Ram
Abstract: Ian Macdonald’s works changed our perspective on so many parts of algebraic combinatorics and formal power series. This talk will display some selected works of the art of Ian Macdonald, representative of different periods of his oeuvre, and analyze how they resonate, both for the past development of our subject and for its future.