To add a seminar or a talk, please email Aram directly. If you want to see math seminars of all disciplines, you can try the following website.

If you want to see old seminars: Videos of Past Conferences/Seminars

I stand in solidarity with the black lives matter movement. You can read my full statement here.

The following is a list of online conferences that are happening during the pandemic! If you have a conference you'd like to add, feel free to email me. đ

- GSCC - Graduate Student Combinatorics Conference
**23 - 25 April 2021** - DMD 2020 - Discrete Math Days Spring 2021
**24 - 25 April 2021** - Diversity and Excellence Workshop - Women in Combinatorics and Representation Thoery
**15 - 16 May 2021** - WAM - Representation theory: Categories and Combinatorics (Program for women)
**22 - 28 May 2021** - SSAC - Summer School of Algebraic Combinatorics
**21 - 25 June 2021** - CIRM: - Lattice Paths, Combinatorics and Interactions
**21 - 25 June 2021** - QTMC - Queer and Trans Mathematicians in Combinatorics
**24 - 25 June 2021**

All times are denoted in your local computer time. Roughly the next two weeks are shown.

It is currently: **Sun 18 Apr 2021 12:44 UTC**

Last updated: Sun 11 Apr 2021 15:53 UTC

Green - Talk is currently happening.

Yellow - Talk is coming up within the hour.

Red - Talk is in under 10 minutes.

**Zoom links can be found on seminar/conference websites** (They have been removed for security reasons)

Speaker | Title | Date & Time | Duration | Abstract | Seminar |
---|---|---|---|---|---|

Naqeeb ur Rehman (AIOU) | The Game of life on Algebraic Universe | Mon 19 Apr 2021 11:00 UTC | Check Seminar Page | No abstract available | LUMS |

Karola MĂ©szĂĄros (Cornell University) | TBA | Mon 19 Apr 2021 15:00 UTC | 50 minutes | No abstract available | AGC |

Hudson Lafayette (Virginia Commonwealth University) | TBA | Mon 19 Apr 2021 18:00 UTC | 60 minutes | No abstract available | Kentucky |

John Blasiak (Drexel University) | TBA | Mon 19 Apr 2021 19:00 UTC | 60 minutes | No abstract available | York |

Daniel I. Bernstein | TBA | Mon 19 Apr 2021 19:00 UTC | Check Seminar Page | No abstract available | MU |

Kelly Isham UC Irvine | On n-arcs in projective space | Mon 19 Apr 2021 19:10 UTC | 50 minutes | Show | Berkeley |

Erika Roldan (Technical University Munic, EPFL) | Topology and local geometry of random and extremal polyominos | Tue 20 Apr 2021 14:00 UTC | 90 minutes | Show | Dartmouth |

Dani Kaufman (University of Maryland) | Mutation Invariant Functions On Cluster Algebras | Tue 20 Apr 2021 16:00 UTC | Check Seminar Page | Show | OCAS |

Derek Hanely (University of Kentucky) | TBA | Wed 21 Apr 2021 17:00 UTC | 60 minutes | No abstract available | GOCC |

Mariel Supina, UC Berkeley | The equivariant Ehrhart theory of the permutahedron (pre-talk) | Wed 21 Apr 2021 22:30 UTC | 30 minutes | Show | UW |

Mariel Supina, UC Berkeley | The equivariant Ehrhart theory of the permutahedron | Wed 21 Apr 2021 23:10 UTC | 50 minutes | Show | UW |

Pedro Tamaroff (MPI MIS, Leipzig) | TBA | Thu 22 Apr 2021 13:15 UTC | 45 minutes | No abstract available | NASO |

Hanson Smith, University of Connecticut | TBA | Thu 22 Apr 2021 16:30 UTC | 50 minutes | No abstract available | Davis |

Dr. Jo Ellis-Monaghan, University of Amsterdam | TBA | Thu 22 Apr 2021 18:00 UTC | Check Seminar Page | No abstract available | WiC |

Rose McCarty (Waterloo) | TBA | Thu 22 Apr 2021 19:00 UTC | Check Seminar Page | No abstract available | PDMS |

Toufik Mansour, University of Haifa | On Stanley-Wilf limit of the pattern 1324 | Thu 22 Apr 2021 21:00 UTC | 48 minutes | Show | REMS |

Brigitte Servatius (Worcester Polytechnic Institute) | Multidimensional tensegrities | Fri 23 Apr 2021 16:00 UTC | 60 minutes | Show | CUNY |

Eugene Gorsky (UC Davis) | TBA | Fri 23 Apr 2021 19:00 UTC | 60 minutes | No abstract available | Michigan |

Speaker | Title | Date & Time | Duration | Abstract | Seminar |
---|---|---|---|---|---|

Anastasia Chavez (UC Davis) | TBA | Mon 26 Apr 2021 18:00 UTC | 60 minutes | No abstract available | Kentucky |

Nancy Wallace (UniversitĂ© du QuĂ©bec Ă MontrĂ©al) | TBA | Mon 26 Apr 2021 19:00 UTC | 60 minutes | No abstract available | York |

Yulia Alexandr UC Berkeley | TBA | Mon 26 Apr 2021 19:10 UTC | 50 minutes | No abstract available | Berkeley |

Stavros Garoufalidis | Knots and their related q-series | Tue 27 Apr 2021 12:00 UTC | 60 minutes | No abstract available | LIPN |

Guillem Perarnau (Universitat PolitĂšcnica de Catalunya) | TBA | Tue 27 Apr 2021 13:00 UTC | Check Seminar Page | No abstract available | Oxford |

Roberto Oliveira (IMPA) | TBA | Tue 27 Apr 2021 14:30 UTC | Check Seminar Page | No abstract available | Oxford |

Peigen Cao (UniversitĂ© de Paris) | TBA | Tue 27 Apr 2021 16:00 UTC | Check Seminar Page | No abstract available | OCAS |

William Gustafson (University of Kentucky) | TBA | Wed 28 Apr 2021 17:00 UTC | 60 minutes | No abstract available | GOCC |

Giulio Codogni (UniversitĂ di Roma "Tor Vergata") | Characterizing Jacobians via the KP equation and via flexes and degenerate trisecants to the Kummer variety: an algebro-geometric approach | Thu 29 Apr 2021 13:15 UTC | 45 minutes | Show | NASO |

Alex Kontorovich, Rutgers University | TBA | Thu 29 Apr 2021 16:30 UTC | 50 minutes | No abstract available | Davis |

Victor S. Miller -- IDA Center for Communications Research, Princeton | Locality preserving hash functions, a partial order and tiles in binary space | Thu 29 Apr 2021 21:00 UTC | 48 minutes | Show | REMS |

Joao Costalonga (Universidade Federal Do Espirito, Brazil) | TBA | Fri 30 Apr 2021 16:00 UTC | 60 minutes | No abstract available | CUNY |

JosĂ© Bastidas Olaya (Cornell University) | TBA | Fri 30 Apr 2021 18:30 UTC | Check Seminar Page | No abstract available | UMass |

Nat Thiem (University of Colorado Boulder) | An introduction to approximating representation theories | Fri 30 Apr 2021 20:30 UTC | 60 minutes | Show | OU |

Lara Bossinger (UNAM) | TBA | Fri 30 Apr 2021 20:35 UTC | 50 minutes | No abstract available | Minnesota |

Mike Zabrocki (York University) | See-saw pairs and set valued tableaux | Tue 04 May 2021 14:00 UTC | 90 minutes | No abstract available | Dartmouth |

Nicolas Libedinsky | TBA | Wed 05 May 2021 15:00 UTC | 60 minutes | No abstract available | RepNet |

Jake Levinson (Simon Fraser University) | TBA | Fri 07 May 2021 20:30 UTC | 60 minutes | No abstract available | OU |

Seminar Code | Name | Institution | Website |
---|---|---|---|

GAPT | Geometry, Algebra, Mathematical Physics and Topology Research Group | Cardiff Univesity | Seminar Website |

ACO | Algorithms, Combinatorics and Optimization Seminar | Carnegie Mellon University | Seminar Website |

CUNY | New York Combinatorics Seminar | City University of New York | Seminar Website |

Colo State | Rocky Mountain Algebraic Combinatorics Seminar | Colorado State University | Seminar Website |

Dartmouth | Dartmouth Combinatorics Seminar | Dartmouth College | Seminar Website |

IMSc | Algebraic Combinatorics Seminar | Institute of Mathematical Sciences | Seminar Website |

LIPN | LIPN Seminar | Laboratoire d'Informatique de Paris Nord | Seminar Website |

LUMS | John Conway Spirited Seminar Series | Lahore University of Management Sciences | Seminar Website |

LACCS | Los Angeles Combinatorics and Complexity Seminar | Los Angeles | Seminar Website |

MHM | MIT-Harvard-MSR Combinatorics Seminar | MIT, Harvard, MSR | Seminar Website |

MIT | Virtual seminar on algebraic matroids and rigidity theory | Massachussetts Institute of Technology | Seminar Website |

MU | Online Matroid Theory Seminar | Matroid Union | Seminar Website |

NASO | Nonlinear Algebra Seminar Online | Max-Planck-Instut fĂŒr Mathematik (MPI) | Seminar Website |

Michigan State | Combinatorics and Graph Theory | Michigan State University | Seminar Website |

VCC | Virtual Combinatorics Colloquium | Northeast Combinatorics Network | Seminar Website |

OU | Algebra and Representation Theory Seminar | Oklahoma University | Seminar Website |

AGC | Algebra, Geometry and Combinatorics | Online | Seminar Website |

Cibercoloquio | Cibercoloquio Latinoamericano de MathemĂĄticas | Online | Seminar Website |

GOCC | Graduate Online Combinatorics Colloquium | Online | Seminar Website |

OCAS | Online Cluster Algebra Seminar | Online | Seminar Website |

Oxford | Oxford Discrete mathematics and probability seminar | Oxford University | Seminar Website |

PDMS | Princeton Discrete Mathematics Seminar | Princeton University | Seminar Website |

RepNet | The RepNet Virtual Seminar | RepNet | Seminar Website |

REMS | Rutgers Experimental Mathematics Seminar | Rutgers University | Seminar Website |

St Petersburg | Workshop on combinatorics, discrete geometry and algorithms | St. Petersburg State University | Seminar Website |

Berkeley | Combinatorics Seminar | UC Berkeley | Seminar Website |

Davis | Algebra and Discrete Mathematics Seminar | UC Davis | Seminar Website |

UCLA | UCLA Combinatorics Seminar | UCLA | Seminar Website |

ACS | Algebraic (and enumerative) combinatorics seminar | UWaterloo | Seminar Website |

SemACT | Seminario de Ălgebra, Combinatoria y TeorĂa de Lie | Universidad Nacional del Sur | Seminar Website |

Colorado | Lie Theory seminar | University of Colorado, Boulder | Seminar Website |

Kentucky | Discrete CATS Seminar | University of Kentucky | Seminar Website |

UMass | Discrete Math Seminar | University of Massachusetts Amherst | Seminar Website |

Michigan | Combinatorics Seminar | University of Michigan | Seminar Website |

Minnesota | Combinatorics Seminar | University of Minnesota | Seminar Website |

USC | USC Combinatorics Seminar | University of Southern California | Seminar Website |

UW | Combinatorics and Geometry Seminar | University of Washington | Seminar Website |

AGT | Algebraic Graph Theory | University of Waterloo | Seminar Website |

UQAM | SĂ©minaire de combinatoire et d'informatique mathĂ©matique du LaCIM | UniversitĂ© du QuĂ©bec Ă MontrĂ©al | Seminar Website |

WUSTL | WUSTL Combinatorics Seminar | Washington University in St. Louis | Seminar Website |

WiC | WinCom Virtual Colloquium | Women in Combinatorics | Seminar Website |

York | Applied Algebra Seminar | York University | Seminar Website |

An n-arc in (k-1)-dimensional projective space is a set of n points so that no k lie on a hyperplane. Understanding the number of n-arcs has been an important area of study in several fields including finite geometry and coding theory. In 1988, Glynn gave an algorithm to count n-arcs in the projective plane of order q in terms of simpler combinatorial objects called superfigurations. Formulas for the number of n-arcs are known for $n \le 9$. In this talk, I will discuss new results about the number of 10-arcs in the projective plane of order q. I will then introduce a generalization of Glynn's framework and use this to produce an algorithm to count n-arcs in 3-dimensional projective space. This talk includes joint work with Nathan Kaplan and Max Weinreich.

CloseDescription:Do you know what algorithm is deciding which piece you get next in a Tetris game? In this talk I will start by answering this question and then I will tell you about several different ways of sampling random polyominoes (polyominoes are like tetrominoes but with any desired amount of squares). We will also analyze how the topological and geometric properties of polyominoes change depending on the distribution that we choose to sample them. Finally, we will have a look at beautiful polyform structures that reach extremal topological properties and that are, as expected, very much unlikely to be observed by any sampling method.

CloseExamples of functions of cluster variables which remain unchanged after mutation arise naturally when studying cluster algebras. They appear as nontrivial elements of upper cluster algebras, elements of a theta basis, trace functions, cluster characters, and Diophantine equations whose solutions are parameterized by a cluster algebra. Interestingly, one often finds that the same mutation invariant function can be interpreted in several distinct ways, but it is not immediately clear why this would be.

I will give a concise definition of a mutation invariant function in terms of an action of the cluster modular group, and give many more interesting examples. I will also discuss a classification of invariants for Dehn twists on surface cluster algebras, and more generally for "cluster Dehn twists" on mutation finite cluster algebras. This is the primary result of my recent PhD thesis.

It is my hope that this classification allows us to begin to see why the same types functions appear in many distinct guises; each of these constructions (theta basis, trace functions, cluster characters, etc.) produce functions which are manifestly mutation invariant.

Ehrhart theory is a topic in geometric combinatorics which involves counting the lattice points inside of lattice polytopes. Stapledon (2010) introduced equivariant Ehrhart theory, which combines discrete geometry, combinatorics, and representation theory to give a generalization of Ehrhart theory that accounts for the symmetries of polytopes. In this talk, I will discuss joint work with Ardila and Vindas-MelĂ©ndez (2020) on answering one of Stapledon's open questions: determining the equivariant Ehrhart theory for the permutahedron, and verifying his Effectiveness Conjecture in this special case.

CloseEhrhart theory is a topic in geometric combinatorics which involves counting the lattice points inside of lattice polytopes. Stapledon (2010) introduced equivariant Ehrhart theory, which combines discrete geometry, combinatorics, and representation theory to give a generalization of Ehrhart theory that accounts for the symmetries of polytopes. In this talk, I will discuss joint work with Ardila and Vindas-MelĂ©ndez (2020) on answering one of Stapledon's open questions: determining the equivariant Ehrhart theory for the permutahedron, and verifying his Effectiveness Conjecture in this special case.

CloseWe present an explicit formula for the generating function for the number of permutations of length $n$ that avoid 1324 in terms of generating functions for permutations that have a kernel shape of length m, m â„2. This allows us to write down a systematic procedure for finding a lower bound for approximating the Stanley-Wilf limit of the pattern 1324.

Joint work with Christian Nassau

We develop an equilibrium stressability criterium for trivalent multidimensional tensegrities. The criterium appears in different languages:

1. Stress monodromies,

2. Surgeries

3. Exact discrete 1-forms

4. In Cayley algebra.

This is joint work with Oleg Karpenkov, Christian Mueller, Gaiane Panina, Herman Servatius, and Dirk Siersma.

In this talk, I will present a completely algebro-geometric proofs of a theorem by T. Shiota, and of a theorem by I. Krichever, characterizing Jacobians of algebraic curves among all irreducible principally polarized abelian varieties. Shiotaâs characterization is given in terms of the KP equation. Kricheverâs characterization is given in terms of trisecant lines to the Kummer variety. I will treat the case of flexes and degenerate trisecants. The basic tool that I will use is a theorem asserting that the base locus of the linear system associated to an effective line bundle on an abelian variety is reduced. This result will allow me to remove all the extra assumptions that were introduced in the theorems by E. Arbarello, C. De Concini, G.Marini, and O. Debarre, in order to achieve algebro-geometric proofs of the results above. This is a joint work with E. Arbarello and G. Pareschi

CloseA "tile" in the space B^n of bit vectors of length n, is a subset S of B^n, such that there is another subset A of B^n so that every element of B^n can be written uniquely in the form a + s, where a in A and s in S. A particular class of tiles are the subsets of minimum weight elements in the cosets of a linear code over GF(2). In systematically investigating locality preserving hash functions, we generated the list of all possible tiles of cardinality <=64 satisfying a certain optimality condition. All but 6 of them turned out to be the sets of minimum weight elements described above. Attempts to prove the same for the remaining 6 remained elusive. Instead we found two computational criteria -- one using linear programming, and the other using combinatorial bin packing, which showed that the remaining 6 could not be tiles.

[Joint with Don Coppersmith, Dan Gordon and Peter Ostapenko]

There are many instances throughout mathematics where the representation theory of algebraic structures becomes prohibitively challenging. In the theory of finite groups, there is a reasonable work-around that is known as a supercharacter theory. The basic idea is to limit attention to modules that are better behaved than irreducible modules, but that still retain many of the nice properties we expect from irreducibles. This talk gives an introduction to this approach with a focus on techniques that might have a chance of extending to other types of algebraic structures. Many such techniques allow the user to tailor a representation theory to specific applications, a process I will illustrate with some examples in combinatorics.

Close