Colloquia

A major challenge in the study of dynamical systems is that of model discovery: turning data into models that are not just predictive, but provide insight into the nature of the underlying dynamical system that generated the data and the best representation of an accompanying coordinate system. This problem is made more difficult by the fact that many systems of interest exhibit parametric dependencies and diverse behaviors across multiple time scales.

The classical Cahn-Hilliard equation [1] is a nonlinear, fourth order in space, parabolic partial differential equation which is often used as a diffuse interface model for the phase separation of a binary alloy. Despite the widespread adoption of the model, there are good reasons for preferring models in which fractional spatial derivatives appear [2,3]. We consider two such Fractional Cahn-Hilliard equations (FCHE).

In this talk, intended for general mathematical audience, I will explain how complex analytic methods have been used to study the distribution of mathematical objects of number theoretic interest in the last couple of centuries, starting with Riemann's approach to proving the Prime Number Theorem. At the end I will sketch some recent progress.

Sobolev embeddings control the integrability of some power of a function by an
integral of the derivative of the function at a lower power. The limiting case
where the latter power is taken to be 1 due to Gagliardo and Nirenberg, is
inaccessible to classical methods of harmonic analysis and turns out to be a
functional version of the isoperimetric inequality. If one considers vector
fields instead of functions, one can hope that some redundancy in the
derivative would allow to obtain estimates with an integrand that does not

Abstract: In this talk, I will look at an old problem of very simple flow on a torus, 
x' = wx + g(x,y)
y' = wy
In particular, I will be interested in the phase-locked states for this system.  A common class of phase models  has the form that
g(x,y) = a(y) sin(x) + b(y) cos(x)
I show that this system is equivalent to a simple  map:
r' = m(r)