Events

Filter by:

Limit to events where the first date of the event:
Date range
Limit to events where the first date of the event:
Limit to events where the title matches:
Limit to events where the type is one or more of:
Limit to events tagged with one or more of:
Limit to events where the audience is one or more of:
Wednesday, November 22, 2017 4:30 pm - 4:30 pm EST (GMT -05:00)

Joint PureMath/C&O Semimar - Mehdi Karimi

Title: Sum-of-Squares Proofs in Optimization

Speaker: Mehdi Karimi
Affiliation: University of Waterloo
Room: MC 5501

Abstract:

The old concept of sum-of-squares found its way into optimization and even machine learning. I will talk about this quickly evolving research area known as convex algebraic geometry.

Thursday, November 23, 2017 1:30 pm - 1:30 pm EST (GMT -05:00)

Special Seminar - Markus Blumenstock

Title: Orientations, Pseudoforests, Flows, and the Densest Subgraph
 

Speaker: Markus Blumenstock
Affiliation: University of Mainz, Germany
Room: MC 6486

Abstract:

Given an undirected graph, consider the problem of finding an orientation such that the max-imum indegree is minimized. The Gabow-Westermann algorithm can solve it by exploiting the matroid structure of pseudoforests.

Friday, November 24, 2017 3:30 pm - 3:30 pm EST (GMT -05:00)

Tutte Colloquium - Joseph Cheriyan

Title: Nash-Williams

Speaker: Joseph Cheriyan
Affiliation: University of Waterloo
Room: MC 5501

Abstract:

Crispin Nash-Williams 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.

Wednesday, November 29, 2017 4:00 pm - 4:00 pm EST (GMT -05:00)

Continuous Optimization Seminar - Leanne Stuive

Title: Efficient First-Order Methods for Linear Programming and Semidefinite Programming 

Speaker: Leanne Stuive
Affiliation: University of Waterloo
Room: MC 5479

Abstract:

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.

Thursday, November 30, 2017 3:30 pm - 3:30 pm EST (GMT -05:00)

Graphs and Matroids - Jim Geelen

Title: Fragility and circuit-hyperplane relaxation

Speaker: Jim Geelen
Affiliation: University of Waterloo
Room : MC 5479

Abstract:

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 N-fragility and of circuit-hyperplane relaxations.

Thursday, November 30, 2017 3:30 pm - 3:30 pm EST (GMT -05:00)

Algebraic Graph Theory Seminar - Nathan Lindzey

Title: Asymmetric Latin squares, Steiner triple systems, and 1-factorizations

Speaker: Nathan Lindzey
Affiliation: University of Waterloo
Room: MC 6486

Abstract:

We outline how the Van der Waerden permanent theorem can be used to show that almost all Latin squares, Steiner triple systems, and 1-factorizations of the complete graph admit only trivial automorphisms. 

Wednesday, December 6, 2017 4:00 pm - 4:00 pm EST (GMT -05:00)

Continuous Optimization - Shenghao Yang

Title: Signal Recovery by Proximal Forward-Backward Splitting

Speaker: Shenghao Yang
Affiliation: University of Waterloo
Room: MC 5479

Abstract:

We will be discussing the paper (bearing the same title) of Patrick Combettes and Valérie Wajs.  We show that various inverse problems in signal recovery can be formulated as the generic problem of minimizing the sum of two convex functions with certain regularity properties.

Thursday, December 7, 2017 3:30 pm - 3:30 pm EST (GMT -05:00)

Algebraic Graph Theory Seminar - Chris Godsil

Title: Continuous Quantum Walks and Symmetric Powers

Speaker: Chris Godsil
Affiliation: University of Waterloo
Room: MC 6486

Abstract:

The k-th symmetric power of a graph X has the k-subsets of V(X) as its vertices, and two k-subsets are adjacent if their symmetric difference is an edge in X. A continuous quantum walk on a graph gives rise in a natural walk to walks on it symmetric powers.