Events

Title: A characterization of (p,q)-mixing when p/q < 4

Abstract: Let Hom(G,H) be the graph whose vertex set is the set of H-colourings of G, and two H-colourings f and g are adjacent if f differs from g in at most one vertex.

Title: The Shapiro-Shapiro Conjecture

Abstract:

Given four lines in 3-space, can you find a fifth line that intersects the other four? How many?

This is the smallest non-trivial example of a "Schubert problem". The answer, in this case, is not hard to compute: there are two such lines. Generalizations of this fact date back to 19th century work of Schubert.

Title: Review of martingale theory, stochastic gradient descent, and adaptive line-line-search for stochastic optimization.

Abstract: With the rise of large data sets, practical algorithms for machine learning often use probability and statistics.

Title: Controllable graphs

Abstract: A graph is controllable if no eigenvector is orthogonal to the all-ones vector.

Title: Representable orientable matroids that are not real-representable

Abstract: In this talk we will have a brief introduction to oriented matroids and their relation to real-representability.

Title: Offline Assisted Group Key Exchange

Abstract:

This talk will focus on the problem of forward secrecy in group key exchange (GKE), where most of the participants remain offline until they wish to compute the key.

Title: Tutorial on back-propagation and automatic differentiation

Abstract: In this presentation, I'll cover the basics of automatic differentiation (AD).

Title: Graphs of Homomorphisms

Abstract: If X and Y are graphs and f is a function on V (X) taking values in V (Y ), then the graph of
f is the subset formed by the pairs (x; f(x)) for x in V (X).

Title: Extending Thomassen’s Theorem to Two Faces

Abstract:

Let G be a planar graph and let L be a list-assignment for G in which there is a precolored edge on the outer face, every other vertex on the outer face has a list of size at least 3, and every other vertex in G has a list of size at least 5.

Title: Primal-dual and Lagrangian relaxation techniques for k-median

Abstract: We will develop primal-dual algorithms to obtain constant-factor approximations for the uncapacitated facility location problem.