Past Seminars
|
Thu, 20/11/2003 16:30 |
Prof A Korobkin (Laventyev) |
Differential Equations and Applications Seminar  |
DH 3rd floor SR |
|
Thu, 20/11/2003 16:30 |
Frederic Patras (Nice) |
Representation Theory Seminar |
SR1 |
|
Thu, 20/11/2003 16:15 |
Ralph Blumenhagen (Cambridge) |
Oxral Series (Fisher Room of NAPL) |
NAPL |
|
Thu, 20/11/2003 14:00 |
Prof Javier Pena (Carnegie Mellon University) |
Computational Mathematics and Applications |
Comlab |
|
Condition numbers are a central concept in numerical analysis.
They provide a natural parameter for studying the behavior of
algorithms, as well as sensitivity and geometric properties of a problem.
The condition number of a problem instance is usually a measure
of the distance to the set of ill-posed instances. For instance, the
classical Eckart and Young identity characterizes the condition
number of a square matrix as the reciprocal of its relative distance
to singularity.
We present concepts of conditioning for optimization problems and for more general variational problems. We show that the Eckart and Young identity has natural extension to much wider contexts. We also discuss conditioning under the presence of block-structure, such as that determined by a sparsity pattern. The latter has interesting connections with the mu-number in robust control and with the sign-real spectral radius. |
|||
|
Thu, 20/11/2003 11:00 |
Advanced Logic Class |
L3 | |
|
Wed, 19/11/2003 12:00 |
Andre Lukas (Sussex) |
String Theory Seminar |
L3 |
| I present a calculation of the moduli Kahler potential for M-theory on a G_2 manifold in a large radius approximation. The result is used to analyze moduli dynamics and moduli stabilization in the context of the associated four-dimensional effective theory. | |||
|
Tue, 18/11/2003 17:00 |
Dr Frederic Patras (Nice) |
Algebra Seminar |
L1 |
|
Tue, 18/11/2003 17:00 |
Richard Smith (Oxford) |
Functional Analysis Seminar |
L3 |
|
Tue, 18/11/2003 15:00 |
Jorge Ramirez-Alfonsin (Paris) |
Combinatorial Theory Seminar |
L3 |
|
Tue, 18/11/2003 12:00 |
Prof E T Newman (Pittsburgh) |
Relativity Seminar |
L3 |
|
Mon, 17/11/2003 17:00 |
Dr Andrew Lorent (Oxford) |
Applied Analysis and Mechanics Seminar |
L1 |
| Take any region omega and let function u defined inside omega be the distance from the boundary, u solves the iconal equation \lt|Du\rt|=1 with boundary condition zero. Functional u is also conjectured (in some cases proved) to be the "limiting minimiser" of various functionals that arise models of blistering and micro magnetics. The precise formulation of these problems involves the notion of gamma convergence. The Aviles Giga functional is a natural "second order" generalisation of the Cahn Hilliard model which was one of the early success of the theory of gamma convergence. These problems turn out to be surprisingly rich with connections to a number of areas of pdes. We will survey some of the more elementary results, describe in detail of one main problems in field and state some partial results. | |||
|
Mon, 17/11/2003 17:00 |
Frank Johnson (UCL) |
Topology Seminar |
L3 |
|
Mon, 17/11/2003 15:45 |
Nadia Sidorova (Oxford) |
Stochastic Analysis Seminar |
DH 3rd floor SR |
| We construct and study different surface measures on the space of paths in a compact Riemannian manifold embedded into the Euclidean space. The idea of the constructions is to force a Brownian particle in the ambient space to stay in a small neighbourhood of the manifold and then to pass to the limit. Finally, we compare these surface measures with the Wiener measure on the space of paths in the manifold. | |||
|
Mon, 17/11/2003 14:15 |
Udo Hertrich-Jeromin (Bath) |
Geometry and Analysis Seminar |
L3 |
|
Mon, 17/11/2003 14:15 |
Mu-Fa Chen (Beijing) |
Stochastic Analysis Seminar |
DH 3rd floor SR |
|
Mon, 17/11/2003 12:00 |
Sanjaye Ramgoolam (Queen Mary, UL) |
String Theory Seminar |
L3 |
| I discuss gauge theories for commutative but non-associative algebras related to the SO(2k+1) covariant finite dimensional fuzzy 2k-sphere algebras. A consequence of non-associativity is that gauge fields and gauge parameters have to be generalized to be functions of coordinates as well as derivatives. The usual gauge fields depending on coordinates only are recovered after a partial gauge fixing.The deformation parameter for these commutative but non-associative algebras is a scalar of the rotation group. This suggests interesting string-inspired algebraic deformations of spacetime which preserve Lorentz-invariance. The talk will be based on hepth/0310153 | |||
|
Fri, 14/11/2003 16:30 |
Boris Zilber (Oxford) |
Logic Seminar |
L3 |
|
Thu, 13/11/2003 16:30 |
Dr J Kobine (University of Dundee) |
Differential Equations and Applications Seminar |
DH 3rd floor SR |
|
Thu, 13/11/2003 16:30 |
Rachel Taillefer (Oxford) |
Representation Theory Seminar |
SR1 |
|
Thu, 13/11/2003 16:30 |
Nina Smith (Bristol) |
Number Theory Seminar |
L2 |
