We discuss some resent results for two type of spectral inequalities in connection with the Navier-Stokes equations. Namely, the Berezin-Li-Yau inequalities for the eigenvalues of elliptic equations and systems ( including the Stokes system) with constant coefficients and the Lieb-Thirring inequalities for the negative spectrum of the Schrodinger operators. In the one-dimensional periodic case we obtain a simultaneous bound for the negative trace and the number of negative eigenvalues.
Whether it is a bottle of soda, the tires of a car or the human body: Objects in everyday life can be described by only a few parameters, like temperature, pressure or volume. But how is this possible, if each of these systems are complex assemblies of atoms and molecules giving rise to a vast number of coordinates, on the order of 10^23?
Ergodic theory is the mathematical attempt to provide an answer to this fundamental question. In this talk we will tackle the problem based on a prominent example - the Einstein model for a solid. It will be shown that this problem is reduced to studying rotations on a circle, for which we will prove a version of the ergodic theorem.
We derive a type of KPZ equation as a scaling limit of fluctuation fields in weakly asymmetric particle systems such as simple exclusion and zero-range processes. Joint work (in progress) with Milton Jara and Patricia Goncalves.
In this talk, we shall consider the near-invisibility cloaking in acoustic scattering by non-singular transformation media. A general lossy layer is included into our construction. We are especially interested in the cloaking of active/radiating objects. Our results on the one hand show how to cloak active contents more efficiently, and on the other hand indicate how to choose the lossy layer optimally.
Waves reflecting/refracting/transmitting from singularities of a metric (e.g. sound speed) satisfy the law of reflection. One expects that if the singularities are sufficiently weak, in terms of differentiability (conormal order) then the reflected singularity is weaker than the transmitted one, in the sense that it is more regular. In this joint work with Maarten de Hoop and Gunther Uhlmann we prove such a result with slightly more regular than C^1 metrics.
We give a proof of the Hölder continuity of weak solutions for the doubly nonlinear parabolic equation in the degenerate case. The analysis discriminates between large scales, for which a Harnack inequality is used, and small scales, that require intrinsic scaling methods. The focus of the talk will be on the precise construction of the sequence of nested and shrinking cylinders where the oscillation of the solution is to be evaluated, and its relation to the structure of the pde. This is a joint work with Tuomo Kuusi and Juhana Siljander (Aalto University, Finland) that will soon appear in Indiana Univ. Math. J.
The California State MATHCOUNTS competition will be taking place at UCI on Saturday, March 17 between 9:00 a.m. - 3:30 p.m. Orange County Regional winners along with other state-wide winners will compete for state titles. The top four participants who earn the honor of representing their state will progress to the national finals.
Event is free and open to the public.
The Orange County Regional MATHCOUNTS competition will be taking place at UCI on Saturday, February 18 between 9:00 a.m. - 3:30 p.m. Our OC mathletes have been coaching for months to finally begin competing! A few of the participating Orange County schools are Rancho San Joaquin Middle School, South Lake Middle School, Lakeside Middle School, Venado Middle School, Bonita Canyon Elementary School, Tarbut Vtorah Day School, Vista Verde School, and Turtle Rock Elementary School. Students will compete individually or as part of a team.