Forthcoming Seminars
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Tue, 18/11/2008 11:00 |
Christopher Larsen (Worcester Polytechnic Institute, USA) |
OxPDE Lunchtime Seminar  |
Gibson 1st Floor SR |
| There has been much recent progress in extending Griffith's criterion for crack growth into mathematical models for quasi-static crack evolution that are well-posed, in the sense that there exist solutions that can be numerically approximated. However, mathematical progress in dynamic fracture (crack growth consistent with Griffith's criterion, together with elastodynamics) has been meager. We describe some recent results on a phase-field model of dynamic fracture, as well as some models based on a "sharp interface" instead of a phase-field. Some possible strategies for showing existence for these last models will also be described. | |||
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Tue, 18/11/2008 15:45 |
Jeff Giansiracusa (Oxford) |
Algebraic and Symplectic Geometry Seminar |
L3 |
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Tue, 18/11/2008 17:00 |
Kay Magaard (Birmingham) |
Algebra Seminar |
L2 |
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Tue, 18/11/2008 17:00 |
Andreas Lubbe (Oxford) |
Functional Analysis Seminar |
L3 |
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Wed, 19/11/2008 11:30 |
Dan Segal (University of Oxford) |
Algebra Kinderseminar |
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Wed, 19/11/2008 14:00 |
Vasily V. Zhikov (Moscow State University and Vladimir State University, Russia) |
OxPDE Lunchtime Seminar |
Gibson 1st Floor SR |
| The Navier-Stokes equation with a non-linear viscous term will be considered, p is the exponent of non-linearity. An existence theorem is proved for the case when the convection term is not subordinate to the viscous term, in particular for the previously open case p<2. The method of proof is based on ideas of the geometric measure theory and compensated compactness. A space-time measure is related to the solution whose existence is proved. This measure may have a singular component. A connection between this singularity and the known results from the partial regularity theory is discussed, in particular for the classical case p=2. | |||
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Wed, 19/11/2008 16:00 |
James Vicary (Comlab) |
Analytic Topology in Mathematics and Computer Science |
L3 |
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Thu, 20/11/2008 11:00 |
Trevor Wood (Oxford) |
Applied Dynamical Systems and Inverse Problems Seminar |
DH 3rd floor SR |
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Thu, 20/11/2008 12:00 |
David Rule (University of Edinburgh) |
OxPDE Lunchtime Seminar |
Gibson 1st Floor SR |
| We study the Neumann and regularity boundary value problems for a divergence form elliptic equation in the plane. We assume the gradient of the coefficient matrix satisfies a Carleson measure condition and consider data in L^p, 1 < p \leq 2. We prove that if the norm of the Carleson measure is sufficiently small, we can solve both the Neumann and regularity problems with data in L^p. This is related to earlier work on the Dirichlet problem by other authors. | |||
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Thu, 20/11/2008 12:00 |
Alan Thompson (Oxford) |
Junior Geometry and Topology Seminar |
SR1 |
| Fibrations are a valuable tool in the study of the geometry of higher dimensional algebraic varieties. By expressing a higher dimensional variety as a fibration by lower dimensional varieties, we can deduce much about its properties. Whilst the theory of elliptic fibrations is very well developed, fibrations by higher dimensional varieties, especially K3 surfaces, are only just beginning to be studied. In this talk I study a special case of the K3-fibration, where the general fibres admit a <2>-polarisation and the base of the fibration is a nonsingular curve. | |||
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Thu, 20/11/2008 14:00 |
Prof Soeren Bartels (University of Bonn) |
Computational Mathematics and Applications |
Comlab |
| Partial differential equations with a nonlinear pointwise constraint defined through a manifold occur in a variety of applications: The magnetization of a ferromagnet can be described by a unit length vector field and the orientation of the rod-like molecules that constitute a liquid crystal is often modeled by a vector field that attains its values in the real projective plane thus respecting the head-to-tail symmetry of the molecules. Other applications arise in geometric modeling, quantum mechanics, and general relativity. Simple examples reveal that it is impossible to satisfy pointwise constraints exactly by lowest order finite elements. For two model problems we discuss the practical realization of the constraint, the efficient solution of the resulting nonlinear systems of equations, and weak accumulation of approximations at exact solutions. | |||
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Thu, 20/11/2008 14:30 |
Reidun Twarock (York) |
Representation Theory Seminar |
L3 |
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Thu, 20/11/2008 16:00 |
Kira Samol (Mainz) |
Number Theory Seminar |
L3 |
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Thu, 20/11/2008 16:30 |
Julius Kaplunov (Brunel) |
Differential Equations and Applications Seminar |
DH 1st floor SR |
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Thu, 20/11/2008 17:00 |
Ayhan Gunaydin (Oxford) |
Logic Seminar |
L3 |
| I will prove that certain pairs of ordered structures are dependent. There are basically two cases depending on whether the smaller structure is dense or discrete. I will discuss the proofs of two quite general theorems which construe the dividing line between these cases. Among examples are dense pairs of o-minimal structures in the first case, and tame pairs of o-minimal structures in the latter. This is joint work with P. Hieronymi. | |||
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Fri, 21/11/2008 09:30 |
Various Speakers |
Industrial and Interdisciplinary Workshops |
DH 1st floor SR |
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Fri, 21/11/2008 11:30 |
Dr Rutger Boels (Niels Bohr Institute) |
Relativity Seminar |
L3 |
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Fri, 21/11/2008 14:15 |
Fausto Gozzi (Luiss) |
Mathematical Finance Seminar |
DH 1st floor SR |
| In this talk we present a work done with M. Di Giacinto (Università di Cassino - Italy) and Salvatore Federico (Scuola Normale - Pisa - Italy). The subject of the work is a continuous time stochastic model of optimal allocation for a defined contribution pension fund with a minimum guarantee. We adopt the point of view of a fund manager maximizing the expected utility from the fund wealth over an infinite horizon. The level of wealth is constrained to stay above a "solvency level". The model is naturally formulated as an optimal control problem of a stochastic delay equation with state constraints and is treated by the dynamic programming approach. We first present the study in the simplified case of no delay where a satisfactory theory can be built proving the existence of regular feedback control strategies and then go to the more general case showing some first results on the value function and on its properties. | |||
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Fri, 21/11/2008 14:30 |
Professor Alastair Rucklidge (Leeds University) |
Mathematical Geoscience Seminar |
DH 3rd floor SR |
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Fri, 21/11/2008 16:30 |
Mohammed Aziz |
Junior Applied Mathematics Seminar |
DH 3rd floor SR |
