Friday April 17, 2026

Hosted by 

Stevens Institute of Technology

New York Combinatorics Day is held once a year at different locations in and around New York City.  Our goal is to provide a learning and sharing experience on recent developments in Combinatorics. Please encourage your graduate and undergraduate students to attend and present a poster.

Location: Stevens Institute of Technology, Room 105 North Building. (Detailed logistics are provided below)

Registration:  There is no registration fee. However, please fill out the registration form since there are room capacity limitations.  The form has space to enter poster information. 

Schedule (in Eastern Time ET)

10:00 am:  Check-In 

10:30 am:  Kira Adaricheva (Hofstra University)

11:30 am: Emilio Minichiello (CUNY Graduate Center)

12:30 pm - 2:30 pm:  Lunch and poster session

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Speaker: Kira Adaricheva (Hofstra University)
Title: Closure Systems with unique critical sets
Abstract: Closure systems are ubiquitous in mathematics and they appear in two major representations: as families of closed set or via implicational bases. In the first form they are lattices, while in the second the implications represent the behavior of the underlying closure operator. The finite join-semidistributive lattices are hard to recognize given their implicational basis. This led to the definition of the class of closure systems with unique critical sets (UC-systems) - naturally defined and recognized via their canonical basis. UC-systems include all (finite) join semidistributive closure systems, as well as their important subclasses: systems without cycles and convex geometries. We will introduce UC-systems and discuss several aspects of them, both structural and algorithmic, as well as offer several open problems. This is the work in progress in collaboration with S. Vilmin (University of Aix-Marseille, CNRS, LIS, France)

Speaker: Emilio Minichiello (CUNY Graduate Center)

Title: Graphs and Homotopy Theory

Abstract: In this talk, I will discuss Lovasz' landmark proof of the Kneser conjecture, which gave a lower bound on the chromatic number of the family of Kneser graphs using a topological invariant. This proof began a long line of research applying methods from homotopy theory to graph theory, now a subfield of topological combinatorics. I'll explain how these ideas motivated a recent paper of mine, and talk about the main theorem from that paper, which more generally relates the homotopy theory of graphs, simplicial complexes and simplicial sets. 

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Poster Session (1:00 - 2:00 pm)

There is a place to enter poster title and abstract on the registration form. Please bring your poster with you on the day of the event. If you have any questions about the poster session, email Professor Kingan (skingan@brooklyn.cuny.edu).

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Logistics: Google Maps will show “North Building Hoboken,” if you type this in, although the technical address is "North Building at 1 Castle Point Terrace."  

From New York City you can take the bus, the Path, or the ferry. The bus will be the best option most of the time, just insofar as minimizing the amount of required walking.

• For the bus, one should take the NJ transit 126 bus from the Port Authority Bus terminal to Washington and 8th. This bus leaves every 10-20 minutes from the port authority from gate 213. Once you are off the bus, walk up 8th (e.g. towards the Hudson River), until you reach the top. North building will be towards your left

• For the Path, take the Path to Hoboken station. Once you arrive you can walk up Hudson street until you get to 8th .

• For the Ferry, there are two possibilities depending on the time and which ferry terminal you leave from. Either take the ferry to Hoboken station (the same station from the previous instruction) or Hoboken 14th street. From the Hoboken 14th street ferry terminal you can walk down 14th street until you hit Hudson street. Then walk down Hudson until you get to 8th.

If you are driving, then set your GPS to “North Building” at 1 Castle Point Ter. in Hoboken. There is no on-campus parking for visitors, so once you arrive you will either have to find street parking, or use one of the various parking garages in town. Note that when it comes to street parking, aside from Washington St., all streets in Hoboken will have one side only accessible to residents of the city. You can only park on sides of the street that have explicit “ParkMobile” signs, which instruct you how to pay for parking. 

For lunch, Stevens is about a 5-10 minute walk from Washington street, which is about a mile long and filled with many, many different restaurants. There should be something for everyone there.

New York Combinatorics Day Steering Committee:
Kira Adaricheva, Sandra Kingan, Anna Pun, Abigail Raz, Eric Rowland