Simon Fraser University

We consider an aggregation model that consists of an active transport equation for the macroscopic population density, where the velocity has a nonlocal functional dependence on the density, modelled via an interaction potential. We set up the model...

Peritrichously flagellated bacteria such as E. coli swim in a fluid environment by rotating motors embedded in the cell membrane and consequently rotating multiple helical flagella. We present a mathematical model of a microswimmer that can freely...

The PPSZ algorithm, due to Paturi, Pudlak, Saks and Zane, is currently the fastest known algorithm for the k-SAT problem, for every k>3. For 3-SAT, a tiny improvement over PPSZ was obtained by Hertli. We introduce a biased version of the PPSZ...

Could an asteroid that explodes over the ocean generate a tsunami threatening coastal populations far away? We show simulations of tsunami propagation from asteroid-generated airbursts. We then present a 1D model with an explicit solution to better...

In this talk I will introduce a new semi-algebraic proof system, called Stabbing Planes that is in the style of DPLL-based modern SAT solvers. Stabbing Planes proofs extend the DPLL branching from single variables to branching on arbitrary linear...

A challenge in descriptive complexity is to identify logics with low complexity that simultaneously express both fundamental reachability properties and counting properties on unordered structures. In this talk, we introduce a family of logics that...

Low Mach number equation sets approximate the equations of motion of a compressible fluid by filtering out the sound waves, which allows the system to evolve on the advective rather than the acoustic time scale. Depending on the degree of...

The aim of structured optimization is to assemble a solution, using a given set of atoms, to fit a model to data. Polarity, which generalizes the notion of orthogonality from linear sets to general convex sets, plays a special role in a simple and...

We consider the Dirichlet problem for a strongly-coupled nonlocal system of equations motivated by peridynamics, a model in continuum mechanics. The strain energy densities involve the magnitude of projected "directional" difference quotients of the...

Neural networks are remarkable families of non-linear functions that form the backbone for state-of-the-art algorithms in tasks from computer vision (self-driving cars), natural language processing (Google Translate) and reinforcement learning...