Past Events

This talk requires no prior knowledge and will be a gentle introduction to colouring graphs. It will be suitable for a broad audience including undergraduates. We will start with some historical tales, including the four colour map problem and the...

On a few examples, such as the permanent of a matrix, (partition function for a system of bosons), matching polynomial of a graph (partition function in a monomer-dimer system), and the independence polynomial of a graph (partition function in the...

In this talk, we will share a new evolutionary but ensemble method, that enable us to track different regimes of behavior and identify when the changes occurred. As opposed to traditional methods that relies on statistical change tracking to detect...

Let B be a normed space and let A be a subspace. When does a continuous linear functional on A admit a unique norm-preserving extension to B? If A and B are C*-algebras and the functional is a so-called pure state, this question was at the heart of a...

Modern machine learning (ML) applications grapple with the challenges posed by high-dimensional datasets and high-dimensional parameter spaces. Stochastic gradient descent (SGD) and its variants have emerged as the go-to algorithms for optimizing in...

Given a convex solid in 3D space, how many light sources do we have to place around it in order to illuminate its entire surface? What is the minimum number that works? We call this number the illumination number of the solid, and perhaps a bit...

Dynamical systems are inevitably subject to noise perturbations, making the study of the stability issues under noise perturbations a fundamental problem. Often used to characterize the complexity of dynamical behaviours, invariant measures...

Recent decades have seen a lot of progress in the "orbital circle method" attacking classical problems from dynamics, geometry, and number theory under the umbrella of "thin groups". There was always a danger that the circle method was too crude a...

The Pythagorean theorem, dating back to before 500 BC, gives a formula for computing the Euclidean distance between two points. It is simply astounding that a concept so simple and classical has continued to fascinate mathematicians over the ages...

We study a single-period optimal transport problem with a cost function given by a general bilinear form and a backward martingale constraint. The role of Kantorovich potentials is played by Fitzpatrick functions. The dual problem is a pseudo...