New York Combinatorics Seminar

This seminar is sponsored by the CUNY Graduate Center's Math Department and Computer Science Department. It covers a wide range of topics in combinatorics and its applications.  Talks are posted on our YouTube channel https://youtube.com/@NYCombinatorics and catalogued on the page Previous Semesters.

Time: Fridays 12:00 pm:  1:00 pm ET (Eastern Time)
Location: The CUNY Graduate Center is located at 365 Fifth Avenue (at the corner of 34th Street), New York. It can be easily reached by subway using the B,D,F,N,Q,R, or 6 train.

Seminar Co-Organizers (alphabetically):  Kira Adaricheva (Hofstra University) Deepak Bal (Montclair State University) Nadia Benakli (City Tech) Jonathan Cutler (Montclair State) Ezra Halleck (City Tech), Sandra Kingan (Graduate Center & Brooklyn College), Joseph Malkevitch (Graduate Center & York College), Kerry Ojakian (BCC), Megan Owen (Graduate Center & Lehman College),  Jinyoung Park (New York University), Anna Pun (Graduate Center & Baruch College), Eric Ramos (Stevens Institute of Technology), (Abigail Raz (Cooper Union), Eric Rowland (Hofstra University), Mingxian Zhong (Graduate Center & Lehman College).

Lead Organizer:

2026 - 2027: Abigail Raz
2025 - 2026: Deepak Bal
2024 - 2025: Anna Pun
2011 - 2024: Sandra Kingan

FALL 2026 TALKS

Room for In-person talks: Graduate Center 9116

Zoom link: https://cooper.zoom.us/j/96616470123?pwd=UE5TIi0AOIRnfJA7XYI1GXUsJZ4G0b.1 

Sep 4: Rosa Orellana (Dartmouth University) (virtual)

Title: The chromatic symmetric function in the star basis

Abstract: In this talk, I will discuss the chromatic symmetric function of a graph, introduced by Stanley in the mid-1990s. Our work is motivated by the Tree Isomorphism Conjecture, which asserts that non-isomorphic trees have distinct chromatic symmetric functions. Aliste-Prieto, De Mier, Zamora, and I introduced the deletion-near-contraction relation, which leads to an algorithm for computing the chromatic symmetric function of a graph in the star basis. This basis provides a useful framework for studying structural properties of graphs that are encoded in the coefficients of their chromatic symmetric functions. I will discuss results concerning trees, unicyclic graphs, and general simple graphs obtained with several co-authors.

Sep 11:  No talk

Sep 18: Pat Devlin (Swarthmore College) (in person)

Title: Rearranging unit cubes to form large monochromatic cubes

Abstract: The faces of unit cubes in $\mathbb{R}^d$ are each colored with one of $\lambda$ colors, and we wish to know how many such cubes are needed until we are guaranteed to find some collection of them that can be arranged into an $n \times n \times \cdots \times n$ cube with monochromatic faces.  We study this problem (and a family of natural intermediate questions) providing asymptotic bounds that differ only by multiplicative constants of the form $C^d$.  In doing so, we prove that this problem is essentially a direct generalization of the longstanding Erdos box problem, a fundamental open question in hypergraph Turan problems.  Our most general bounds are given in terms of the Erdos box problem, which we use essentially as a black box.  However, for a wide range of parameters, we show that the answer to our problem does not depend on the details of the not-yet-resolved Erdos box problem, and we are able to completely settle the asymptotics of our problem in those regimes (up to constants depending only on $d$). This is joint work with Ethan Berkove

Sep 25: Quentin Dubroff (Carnegie Mellon University) (in person)

Title: Faster random walks via infrequent steering

Abstract: Random walks on graphs can be slow. To speed them up, imagine that at each step instead of choosing the neighbor at random, there is a small probability ε>0 that we can choose it. We show that in this case, at least for graphs of bounded degree, there is a way to steer the walk so that we visit every vertex in n1+o(1) steps with high probability. The key to this result is a way to decompose arbitrary graphs into small-diameter pieces. Joint work with Boris Bukh.

Oct 2:  Kristina Wicke (New Jersey Institute of Technology) (in person)

Oct 9: Sebastian Cioaba (University of Delaware) (virtual)

Oct 16: Jade Nichols (MoMath) (in person)

Oct 23: No Talk

Sat Oct 24: Eighty Second Graph Theory Day of New York @ Seton Hall University

Oct 30: Sam Spiro (Georgia State University) (virtual)

Nov 6: J. B. Nation (University of Hawaii) (virtual)

Nov 13: Beth Anne Castellano (Dartmouth University) (virtual)

Nov 20: Mehtaab Sawhney (Columbia University) (virtual)

Nov 27: Holiday (Thanksgiving)

Dec 4: Adam Sheffer (Baruch College) (in person)

Dec 11: Eric Ramos (Stevens Institute of Technology)  (in person)
  

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Previous Speakers:

Spring 2026
Fall 2025
Spring 2025
Fall 2024
Spring 2024
Fall 2023
Spring 2023
Fall 2022
Spring 2022
Fall 2021
Spring 2021
Fall 2020
Spring 2020
Fall 2019
Spring 2019
Fall 2018
Spring and Summer 2018
Fall 2017
Spring 2017
Fall 2016
Spring 2016
Fall 2015
Spring 2015
Fall 2014
Spring 2014
Fall 2013
Spring 2013
Fall 2012
Spring 2012
Fall 2011
Spring 2011
Previous Talks hosted by Janos Pach

Previous Organizers:
Christopher Hanusa (2011 - 2015)