Mon, 16 May 2016

14:15 - 15:15
C6

Heat equation driven by a space-time fractional noise

AURELIEN DEYA
(university of Lorraine France)
Abstract

The extension of standard stochastic models (SDEs, SPDEs) to general fractional noises is known to be a tricky issue, which cannot be studied within the classical martingale setting. We will see how the recently-introduced theory of regularity structures allows us to overcome these difficulties, in the case of a heat equation model with non-linear perturbation driven by a space-time fractional Brownian motion.

The analysis relies in particular on the exhibition of an explicit process at the core of the dynamics, the so-called K-rough path, the definition of which shows strong similarities with that of a classical rough path.

Mon, 09 May 2016

15:45 - 16:45
C6

Global quantizations with and without symmetries

MICHAEL RUZHANSKY
(Imperial College London)
Abstract

In this talk we will give an overview of the recent research on global quantizations on spaces of different types: compact and nilpotent Lie groups, general locally compact groups, compact manifolds with boundary.

Mon, 09 May 2016

14:15 - 15:15
C6

Gaussian Heat-kernel for the RCM with unbounded conductances

OMAR BOUKHADRA
(University of Constantine 1)
Abstract

The talk will focus on continuous time random walk with unbounded i.i.d. random conductances on the grid $\mathbb{Z}^d$  In the first place, in a joint work with Kumagai and Mathieu, we obtain Gaussian heat kernel bounds and also local CLT for bounded from above and not bounded from below conductances. The proof is given at first in a general framework, then it is specified in the case of plynomial lower tail conductances. It is essentially based on percolation and spectral analysis arguments, and Harnack inequalities. Then we will discuss the same questions for the same model with i.i.d. random conductances, bounded from below and with finite expectation.

Recovering from selection bias using marginal structure in discrete models
Evans, R Didelez, V CEUR Workshop Proceedings volume 1504 46-55 (01 Jan 2015)
Optical conductivity of the Hubbard chain away from half filling
Tiegel, A Veness, T Dargel, P Honecker, A Pruschke, T McCulloch, I Essler, F Physical Review B volume 93 issue 12 (03 Mar 2016)
Thu, 02 Jun 2016

14:00 - 15:00
L5

CUR Matrix Factorizations: Algorithms, Analysis, Applications

Professor Mark Embree
(Virginia Tech)
Abstract
Interpolatory matrix factorizations provide alternatives to the singular value decomposition for obtaining low-rank approximations; this class includes the CUR factorization, where the C and R matrices are subsets of columns and rows of the target matrix.  While interpolatory approximations lack the SVD's optimality, their ingredients are easier to interpret than singular vectors: since they are copied from the matrix itself, they inherit the data's key properties (e.g., nonnegative/integer values, sparsity, etc.). We shall provide an overview of these approximate factorizations, describe how they can be analyzed using interpolatory projectors, and introduce a new method for their construction based on the
Discrete Empirical Interpolation Method (DEIM).  To conclude, we will use this algorithm to gain insight into accelerometer data from an instrumented building.  (This talk describes joint work with Dan Sorensen (Rice) and collaborators in Virginia Tech's Smart Infrastucture Lab.)

diophantine equation is an algebraic equation, or system of equations, in several unknowns and with integer (or rational) coefficients, which one seeks to solve in integers (or rational numbers). The study of such equations goes back to antiquity. Their name derives from the mathematician Diophantus of Alexandria, who wrote a treatise on the subject, entitled Arithmetica.

Quench dynamics and relaxation in isolated integrable quantum spin chains
Essler, F Fagotti, M Journal of Statistical Mechanics: Theory and Experiment volume 2016 issue June (01 Jun 2016)
Possibilities determine the combinatorial structure of probability polytopes
Abramsky, S Mansfield, S Kishida, K Lal, R Barbosa, R Journal of Mathematical Psychology volume 74 58-65 (17 May 2016)
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