CombinaTexas Conferences

CombinaTexas 2022

CombinaTexas, a combinatorics conference in the South-Central United States, is an annual regional conference on Combinatorics, Graph Theory, and Computing. It is dedicated to the enhancement of both the educational and research atmospheres of the community of combinatorialists and graph theorists in Texas and the surrounding states. The aim of the CombinaTexas series is to increase communication between mathematicians in the region, promote the research of the regional combinatorics community, and provide a forum for presentation and discussion of developments in the field of combinatorics.

For more information about the CombinaTexas series, click here.

Basic Information

Texas A&M University,
College Station, TX,
March 4-5, 2022.
The conference will in-person.
We plan to have most of the activities in Saturday, March 5. Depending on the number of contributed talks, we may start the conference in the evening of Friday, March 4.

Registration

Registration Form
✽ There is no registration fee. But one must register to attend the conference.

Deadline for registration is Feb 18, 2022. After that one cannot apply for financial aid or submit contributed talks.

Support

A limited amount of support is available. The conference will book hotel rooms for one night (March 4) for participants who requested financial aid. (Graduate students and postdocs may need to share a double room.) In addition, there is a small amount of support for travel expenses, for which we will give priority to graduate students and recent Ph.Ds with contributed talks. If you are applying for the travel support, please indicate the estimated amount of airfare.
The application for support, as well as submission of contributed talks, should be done through the on-line registration form. The deadline is February 18, 2022.

Plenary Speakers

• Kassie Archer , University of Texas--Tyler.
  • Title: +Permutations from Dynamical Systems
    We can obtain permutations, or patterns, of a dynamical system on a totally ordered set from the relative order of the initial segments of orbits. For a given map, we call a pattern "allowed" if it realized this way and "forbidden" if not. We will discuss interesting properties of allowed and forbidden patterns and some consequences for enumerative combinatorics.
• Anton Dochtermann , Texas State University.
  • Title: + Homomorphism complexes, reconfiguration, and homotopy for digraphs
    The study of graph colorings (and more general homomorphisms) has been an active area of research for many years, with numerous applications and various tools brought to bear. Topological methods were introduced to the field via Lovász's neighborhood complex, and more general homomorphism (Hom) complexes of graphs were further studied by Babson and Kozlov. In joint work with Anurag Singh, we initiate the detailed study of Hom complexes for *directed graphs* (digraphs), which have applications in the study of graded posets and resolutions of monomial ideals. We relate the topological properties of Hom complexes to various digraph operations and also introduce the notion of a neighborhood complex for a directed graph. Our complexes provide a natural notion of reconfiguration in this setting, where one is interested in sampling from the space of digraph homomorphisms via walks in the 1-skeleton. We in particular study the connectivity of Hom complexes into tournaments T_n, obtaining a complete answer for the case of transitive T_n. Finally we use paths in the internal hom objects of directed graphs to define various notions of homotopy, and discuss connections to the topology of Hom complexes.
• Jian Shen , Texas State University.
  • Title: + The Towers of Hanoi Problem and the Frame-Stewart Conjecture
    The multi-peg Towers of Hanoi problem consists of k pegs mounted on a board together with n disks of different sizes. Initially these disks are placed on one peg in order of size, with the largest on the bottom. The rules of the problem allow disks to be moved one at a time from one peg to another as long as no disk is placed on the top of a smaller disk. The goal of the problem is to transfer all the disks to another peg with the minimum number of moves, denoted H(n,k). An easy recursive argument shows that H(n, 3)= 2^n -1. However, the value of H(n,k) is unknown for each k > 3. In this talk, we will discuss some upper and lower bounds on H(n,k). Some variations of the Tower of Hanoi problems will also be considered.
• Nathan Williams , University of Texas at Dallas
  Title: + Pop-Tsack Torsing
  Given a finite irreducible Coxeter group W, we use the W-noncrossing partition lattice to define a Bessis dual version of C. Defant’s notion of a Coxeter pop-stack sorting operator. We show that if W is coincidental or of type D, then the identity element of W is the unique periodic point of this operator and the maximum size of a forward orbit is the Coxeter number of W. In each of these types, we obtain a natural lift from W to the dual braid monoid of W. This is joint work with C. Defant.

Schedule and Abstracts (Central Standard Time)

All the academic activities will be held at Blocker Building, third floor on the Texas A&M Campus. This is where the Math Dept locates. Here is an interactive campus map .

Schedule and Abstracts of All Talks

Location, Transportation, Parking

All the activities will be held at the third floor of Blocker Building on the campus of Texas A&M University.

The Northside Garage (NSG) is located directly across from the Blocker Building (BLOC) and has space for visitor parking. (One needs to pay if park here.) During the weekend, you can also park for free at any un-reserved space in a numbered lot, such as Lot 47 and Lot 51. (On the northwest side of the campus, near Univesity Drive and the Bon Fair Memorial)

The interactive campus map also lists available parking lots. Move to the rigth side to see the parking lots 47 and 51.

For details, see Special Parking Regulations at TAMU

Night and weekend parking is available 5 pm to 6 am for valid permit holders in unrestricted/unnumbered spaces in most lots except lots 30, 40, 72, 99 and 122. Night and weekend parking at West Campus Garage begins at 4pm.

No permit is required in unrestricted or plain marked spaces on Saturday, Sunday, or days when the University is officially closed. Exceptions include Lot 30, 40, 72, 99, 122, the golf lot, special event parking and athletic events. Notifications are posted at the entrance to the lot(s) affected during these events.

Warning: Please avoid the west campus and the parking lot 61, 74, 97, 104 and 100s-- They are near the sports facility. On March 5, they are for event-parking only (Aggie Men's Basketball and Baseball) and require a parking permit.

Hotels