Contact Info
Combinatorics & Optimization
University of Waterloo
Waterloo, Ontario
Canada N2L 3G1
Phone: 5198884567, ext 33038
PDF files require Adobe Acrobat Reader.
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Title: Cyclic sieving with focus on open problems
Speaker:Per Alexandersson
Affiliation:Stockholm University
Room/Zoom: MC5479 or for Zoom link contact Logan Crew or Olya MandelshtamAbstract:
The cyclic sieving phenomenon (CSP) connects a cyclic group action on a family of combinatorial objects with some qanalog of that set. We discuss some recent results and open problems for standard and semistandard tableaux, as well as some other families of combinatorial objects.
Several open problems with various levels of difficulty will be presented.
AlCoVE aims to bring together researchers interested in algebraic combinatorics from around the world. Each talk will be 30 minutes and between talks, there will be casual social activities for spending time with your friends and making new friends.
To access the Zoom links, you must first register for the conference.
Registration
To register, click here.
Title: Distance magic labeling on directed graphs
Speaker:Alison Marr
Affiliation:Southwestern University
Zoom: Contact Sabrina Lato for linkAbstract:
This talk will explore two new types of distance magic labelings on directed graphs. Results on some specific classes of directed graphs will be discussed. We will also look at various properties of these two types of labelings and some construction techniques.
Title: Linear arboricity of sparse multigraphs via orientations
Speaker: Ronen Wdowinski Affiliation: University of Waterloo Room: MC 5417Abstract:
The linear arboricity $la(G)$ of a loopless multigraph $G$ is the minimum number of colors required to edgecolor $G$ into linear forests, that is, forests whose components are all paths. The Linear Arboricity Conjecture of Akiyama, Exoo, and Harary asserts that the linear arboricity of a simple graph $G$ is at most $\lceil (\Delta(G)+1)/2 \rceil$.
Title: Generalized Subspace Subcode with Application in Cryptology
Speaker: Jean Belo Klamti Affiliation: University of Waterloo Attend: Contact Jesse ElliottAbstract:
Most codes with an algebraic decoding algorithm are derived from ReedSolomon codes. They are obtained by taking equivalent codes, for example Generalized ReedSolomon codes, or by using the socalled subfield subcode method, which leads to Alternant codes over the underlying prime field, or over some intermediate subfield. The main advantage of these constructions is to preserve both the minimum distance and the decoding algorithm of the underlying ReedSolomon code.
Title: Virtual characters of permutation statistics
Speaker: Zachary Hamacker Affiliation: University of Florida Room: MC 5483Abstract:
Functions of permutations are studied in a wide variety of fields including probability, statistics and theoretical computer science. I will introduce a method for studying such functions using representation theory and symmetric functions. As a consequence, one can extract detailed information about asymptotic behavior of many permutation statistics with respect to nonuniform measures that are invariant under conjugation. The key new tool is a combinatorial formula called the path MurnaghanNakayama rule that gives the Schur expansion of a novel basis of the ring of symmetric functions. This is joint work with Brendon Rhoades.
Title: Algebraic Graph Theory
Speaker: Sabrina Lato Affiliation: University of Waterloo Location: MC 6029Abstract:
A graph is distanceregular if we can write the distance adjacency matrices as polynomials in the adjacency matrix. Distanceregular graphs are a class of graphs of significant interest to algebraic graph theorists for their structural and algebraic properties. The notion of distanceregularity can be weakened to a local property on vertices, but when every vertex in the graph is locally distanceregular, the graph will either be distanceregular or in the closely related class of distancebiregular graphs.
Title: Combinatorial atlas for logconcave inequalities
Speaker: Swee Hong Can Affiliation: UCLA Location: MC 5501 or please contact Melissa Cambridge for Zoom linkAbstract:
The study of logconcave inequalities for combinatorial objects have seen much progress in recent years. One such progress is the solution to the strongest form of Mason’s conjecture (independently by Anari et. al. and BrándënHuh).
Title: Maximal cliques in strongly regular graphs
Speaker: Gary Greaves Affiliation: Nanyang Technological University Zoom: Please contact Sabrina Lato for zoom linkAbstract: In this talk, I will introduce a cubic polynomial that can be associated to a strongly regular graph Γ. The roots of this polynomial give rise to upper and lower bounds for the size of a maximal clique in Γ. I will explain how we can use this cubic polynomial to rule out the existence of strongly regular graphs that correspond to an infinite family of otherwise feasible parameters. This talk is based on joint work with Jack Koolen and Jongyook Park.
Title: Theorems and Exchange Graph Algorithms concerning Paths, Cycles and Trees
Speaker Kathie Cameron Affiliation: Wilfred Laurier University Room: MC 6029Abstract: Carsten Thomassen and I proved that in any graph G, the number of cycles containing a specified edge as well as all the odddegree vertices is odd if and only if G is eulerian. Where all vertices have even degree this is a theorem of Sunichi Toida and where all vertices have odd degree it is Andrew Thomason's generalization of Smith's Theorem.
Title: 1skeleton posets of Bruhat interval polytopes
Speaker Christian Gaetz Affiliation Harvard University Room: MC 5479 or please contact Olya Mandelshtam for Zoom LinkAbstract: Bruhat interval polytopes are a wellstudied class of generalized permutohedra which arise as moment map images of various toric varieties and totally positive spaces in the flag variety. I will describe work in progress in which I study the 1skeleta of these polytopes, viewed as posets interpolating between weak order and Bruhat order. In many cases these posets are lattices and the polytopes, despite not being simple, have interesting hvectors.
Title: An Introduction to Nonnegativity and Polynomial Optimization
Speaker: Timo de Wolff Affiliation: TU Braunschweig Location: MC 5501 or please contact Melissa Cambridge for Zoom linkAbstract:
In science and engineering, we regularly face polynomial optimization problems, that is: minimize a real, multivariate polynomial under polynomial constraints. Solving these problems is essentially equivalent to certifying of nonnegativity of real polynomials  a key problem in real algebraic geometry since the 19th century.
Title: ErdősKoRado results for flags in spherical buildings
Speaker: Sam Matteus Affiliation: Vrije Universiteit Brussel Zoom: Please contact Sabrina Lato for zoom linkAbstract: Over the last few years, ErdősKoRado theorems have been found in many different geometrical contexts including for example sets of subspaces in projective or polar spaces. A recurring theme throughout these theorems is that one can find sharp upper bounds by applying the DelsarteHoffman coclique bound to a matrix belonging to the relevant association scheme.
Title: An into introduction to the chromatic number of digraph
Speaker: Alvaro Carbonero Gonzales Affiliation: University of Waterloo Room: MC 5417, please contact Shalya Redlin for zoom linkAbstract: A proper $k$coloring of a digraph $D$ is a coloring of the vertices such that every color class is acyclic, and the dichromatic number of a digraph $D$ is the minimum number $k$ such that there is a proper $k$coloring of $D$. Many questions about the chromatic number can be asked about the dichromatic number, but as one will quickly observe, unsuspected complications arise when dealing with digraphs.
Title: On the Security of the NIST lightweight Finalist Ascon
Speaker: Raghvendra Rohit Affiliation: Technology Institute in Abu Dhabi Zoom: Please contact Jesse Elliott for zoom linkAbstract:
The ongoing NIST lightweight cryptographic standardization project for the selection of ciphers which are suitable for constrained environments is in the final stage. The authenticated encryption algorithm Ascon, designed by Dobrauing et al., is one out of the 10 finalists. Ascon is also one of the winners of the CAESAR competition in the lightweight applications category.
Title: A Brief Introduction to World of Erd\H{o}sKoRado Theorems
Speaker: Karen Meagher Affiliation: University of Regina Zoom: Please contact Sabrina Lato for Zoom linkAbstract: The Erd\H{o}sKoRado (EKR) theorem is a famous result that is one of the cornerstones of extremal set theory. This theorem answers the question "What is the largest family of intersecting sets, of a fixed size, from a base set?"
Title: Determinantal formulas with major indices
Speaker: Thomas McConville Affiliation: Kennesaw State Room: MC 5483Abstract: Krattenthaler and Thibon discovered a beautiful formula for the determinant of the matrix indexed by permutations whose entries are q^maj( u*v^{1} ), where “maj” is the major index. Previous proofs of this identity have applied the theory of nonsymmetric functions or the representation theory of the Tits algebra to determine the eigenvalues of the matrix.
Combinatorics & Optimization
University of Waterloo
Waterloo, Ontario
Canada N2L 3G1
Phone: 5198884567, ext 33038
PDF files require Adobe Acrobat Reader.
The University of Waterloo acknowledges that much of our work takes place on the traditional territory of the Neutral, Anishinaabeg and Haudenosaunee peoples. Our main campus is situated on the Haldimand Tract, the land granted to the Six Nations that includes six miles on each side of the Grand River. Our active work toward reconciliation takes place across our campuses through research, learning, teaching, and community building, and is coordinated within the Office of Indigenous Relations.