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: Independence Polynomials and Their Roots
Speaker: Jason Brown Affiliation: Dalhousie University Room: MC 5417Abstract:
Independence polynomials are generating functions for the number of independent sets of each cardinality in a graph G.
Title: Signings and induced subgraphs of the Hypercube
Speaker: Maxwell Levit Affiliation: University of Waterloo Room: MC 5479Abstract:
Just over a month ago, Hao Haung resolved the sensitivity conjecture, a 30 yearold question about the complexity of boolean functions.
Title: Approximation Algorithms for MinimumNorm Optimization Problems
Speaker: Chaitanya Swamy Affiliation: University of Waterloo Room: MC 5501Abstract:
In many optimization problems, a feasible solution induces a multidimensional cost vector. For example, in kclustering, opening k facilities induces an assignmentcost vector indexed by the clients; in loadbalancing, a schedule induces a load vector across the machines.
Title: Polynomial Spaces
Speaker: Chris Godsil Affiliation: University of Waterloo Room: MC 5417Abstract:
We describe some simple machinery that enables us to derive upper bounds on the size of codes, and lower bounds on the size of designs in a quite general setting.
Title: Combinatorial questions motivated by Invariant Theory
Speaker: Matthew Satriano Affiliation: University of Waterloo Room: MC 5417Abstract:
We begin the talk by discussing a question in Invariant Theory: given a representation $V$ of a Lie group $G$, when if the invariant ring $k[V]^G$ a polynomial ring? We give a conjectural answer which we have verified for $SL_n$ and discuss some combinatorial questions motivated by the proof. This is joint work with Dan Edidin.
Title: Monochromatic cycle partitions
Speaker: Richard Lang Affiliation: University of Waterloo Room: MC 5501Abstract:
A classic result of Erdős, Gyárfás, and Pyber states that the vertex set of every complete graph, whose edges have been coloured with r colours, can be covered by r2 log r disjoint monochromatic cycles.
Title: Orthogonal Polynomials and the Addition Formula
Speaker: Chris Godsil Affiliation: University of Waterloo Room: MC 5479Abstract:
Many questions about designs and codes in the unit sphere can be reduced to questions about members of a family of orthogonal polynomials, the socalled Gegenbauer polynomials.
Title: When are two Schur functions the same?
Speaker: Nick OlsonHarris Affiliation: University of Waterloo Room: MC 5417Abstract:
A pair of skew shapes are said to be (skew) equivalent if they admit the same number of semistandard tableaux of any weight; i.e. if their associated skew Schur functions are equal.
Title: The sparsest matroids omitting an independent flat
Speaker: Peter Nelson Affiliation: University of Waterloo Room: MC 5501Abstract:
Given integers $k,r \ge 1$, what is the smallest a rank$r$ matroid can be that does not contain a $k$element independent set that is also a flat? I will answer this question, characterize the extremal examples, and draw parallels with a problem in graph theory.
Title: Undermining key exchange
Speaker: Douglas Stebila Affiliation: University of Waterloo Room: MC 5501Abstract:
There are many ways to undermine systems that rely on cryptography. An attacker could of course try to find flaws in the hardware and software implementing the system, or find mathematical weaknesses in the cryptographic algorithms.
Title: Improving Implementations of CSIDH
Speaker: Jason LeGrow Affiliation: University of Waterloo Room: MC 5417Abstract:
I will present on some papers related to implementations of CSIDH [1].
Title: LP bounds and the addition formula
Speaker: Chris Godsil Affiliation: University of Waterloo Room: MC 5479Abstract:
I will show how we can derive useful bounds on the size of codes and designs, using linear programming and the addition formula.
Title: Chord diagrams, generating functions, and qft
Speaker: Karen Yeats Affiliation: University of Waterloo Room: MC 5417Abstract:
I'll talk about some joint work with Julien Courtiel where some nice enumerative combinatorics tells us something about how gauge theories are such special quantum field theories.
Title: Submodular function maximization
Speaker: Chaitanya Swamy Affiliation: University of Waterloo Room: MC 5501Abstract:
I will give the introductory talk for this term's topic for the CombinatorialOptimization Reading group, namely submodular function maximization. Submodular functions arise in diverse contexts in combinatorial optimization.
Title: Countable weighted graphs with no unfriendly partitions
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.