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Title: A Stochastic Gradient Method with an Exponential Convergence Rate for Finite Training Sets
Speaker: Ryan Kinnear Affiliation: University of Waterloo Room: MC 5479Abstract:
We will be discussing the paper (having the same title) by Roux, Schmidt, and Bach. The authors propose a new stochastic gradient method for optimizing the sum of a finite set of smooth functions, where the sum is strongly convex.
Title: A short proof of a forgotten result
Speaker: Bertrand Guenin Affiliation: University of Waterloo Room: MC 4042Abstract:
Title: How we solve linear programs
Speaker: Laurent Poirrier Affiliation: University of Waterloo Room: MC 5501Abstract:
Linear programming is one of the most fundamental tools in optimization, and its theoretical complexity is well understood. In practice though, things are quite different: Which types of problems can we really solve? What sizes? With what algorithms?
Title: A Fast Iterative ShrinkageThresholding Algorithm for Linear Inverse Problems
Speaker: Nargiz Kalantarova Affiliation: University of Waterloo Room: MC 5479Abstract:
We will be discussing the paper (having the same title) by Amir Beck and Marc Teboulle. We consider the class of iterative shrinkagethresholding algorithms (ISTA) for solving linear inverse problems arising in signal/image processing. This class of methods, which can be viewed as an extension of the classical gradient algorithm, is attractive due to its simplicity and thus is adequate for solving largescale problems even with dense matrix data.
Title: An Introduction to Discrete Quantum Walks
Speaker: Harmony Zhan Affiliation: University of waterloo Room: MC 6486Abstract:
We will introduce the concept of a discrete quantum walk, prove some of its properties, discuss its relation to different graph structures, and construct interesting walks from these structures such as selfdual embeddings.
Title: An application of graph "recolouring”
Speaker: Ben Moore Affiliation: University of Waterloo Room: MC 5479Abstract:
I will prove that for any graph G, if there is an edge e such that Ge has less than (k1)!/2 cycles of length zero mod k, then the chromatic number of G is less or equal to k.
Title: Coloring (cap even hole)free graphs
Speaker: Shenwei Huang Affiliation: Wilfrid Laurier University Room: MC 5501Abstract:
An even cycle of length 4 or more is called an even hole. A cap is a cycle of length at least 5 with exactly one chord and that chord creates a triangle with the cycle. In this talk we consider (cap, even hole)free graphs, i.e., graphs that do not contain any even hole or cap as an induced subgraph.
Title: Proximal alternating linearized minimization for nonconvex and nonsmooth problems
Speaker: Stefan Sremac Affiliation: University of Waterloo Room: MC 5479Abstract:
We will be discussing the paper (having the same title) by Jerome Bolte, Shoham Sabach and Marc Teboulle. We introduce a proximal alternating linearized minimization (PALM) algorithm for solving a broad class of nonconvex and nonsmooth minimization problems.
Title: Constructing cospectral graphs with a different switching
Speaker: Chris Godsil Affiliation: University of Waterloo Room: MC 6486Abstract:
Many years ago, Brendan McKay and I introduced a construction of pairs of cospectral graphs, sometimes known as local switching. In the same paper we introduced a second switching technique which produces, as special cases, the smallest pair of cospectral graphs and the smallest pair of connected cospectral graphs.
Title: Convex drawings of complete graphs: topology meets geometry
Speaker: Bruce Richter Affiliation: University of Waterloo Room: MC 5479Abstract:
A drawing D of the complete graph K(n) is the sphere is characterized by, for each isomorph J of K(5), D[J] is homeomorphic to one of the three rectilinear drawings of K(5). Every drawing of K(n) in the plane with all edges straightline segments is obviously convex. Thus, convex drawings generalize planar point sets that are in general position.
Title: Recent Advances in FrankWolfe Optimization
Speaker: Simon LacosteJulien Affiliation: University of Montreal Room: MC 5501Abstract:
The FrankWolfe (FW) optimization algorithm has lately regained popularity thanks in particular to its ability to nicely handle the structured constraints appearing in machine learning and signal processing applications. However, its convergence rate is known to be slow (sublinear) when the solution lies at the boundary.
Title: Alternating Direction Method of Multipliers for the SDP Relaxation of the Quadratic Assignment Problem
Speaker: Henry Wolkowicz Affiliation: University of waterloo Room: MC 5479Abstract:
The semidefinite programming (SDP) relaxation has proven to be extremely strong for many hard discrete optimization problems. This is in particular true for the quadratic assignment problem (QAP), arguably one of the hardest NPhard discrete optimization problems.
Title: SumofSquares Proofs in Optimization
Speaker: Mehdi Karimi Affiliation: University of Waterloo Room: MC 5501Abstract:
The old concept of sumofsquares found its way into optimization and even machine learning. I will talk about this quickly evolving research area known as convex algebraic geometry.
Title: Orientations, Pseudoforests, Flows, and the Densest Subgraph
Abstract:
Given an undirected graph, consider the problem of finding an orientation such that the maximum indegree is minimized. The GabowWestermann algorithm can solve it by exploiting the matroid structure of pseudoforests.
Title: Ramsey theory for biased graphs
Speaker: Peter Nelson Affiliation: University of Waterloo Room: MC 5479Abstract:
We discuss the unavoidable subgraphs of biased graphs whose underlying graph is a clique.
Title: NashWilliams
Speaker: Joseph Cheriyan Affiliation: University of Waterloo Room: MC 5501Abstract:
Crispin NashWilliams was one of the founding professors of C&O. The talk will cover a small sample of his mathematical work, and also his association with C&O.
Title: Efficient FirstOrder Methods for Linear Programming and Semidefinite Programming
Speaker: Leanne Stuive Affiliation: University of Waterloo Room: MC 5479Abstract:
We will be discussing the paper (bearing the same title) of James Reneger. We present a simple transformation of any linear program or semidefinite program into an equivalent convex optimization problem whose only constraints are linear equations. The objective function is defined on the whole space, making virtually all subgradient methods be immediately applicable.
Title: Asymmetric Latin squares, Steiner triple systems, and 1factorizations
Speaker: Nathan Lindzey Affiliation: University of Waterloo Room: MC 6486Abstract:
We outline how the Van der Waerden permanent theorem can be used to show that almost all Latin squares, Steiner triple systems, and 1factorizations of the complete graph admit only trivial automorphisms.
Title: Fragility and circuithyperplane relaxation
Speaker: Jim Geelen Affiliation: University of Waterloo Room : MC 5479Abstract:
I will briefly discuss the problem of trying to determine the excluded minors for the class of GF(5)representable matroids, highlighting the roles of Nfragility and of circuithyperplane relaxations.
Please email any errors or updates to our website support/editor.
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