Forthcoming Seminars
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Thu, 29/01/2009 09:00 |
Duvan Henao and Christoph Ortner (Oxford University Mathematical Institute) |
OxMOS Workshop/Meeting/Lecture  |
Gibson 1st Floor SR |
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Thu, 29/01/2009 11:00 |
Dr Irene Moroz (Oxford) |
Applied Dynamical Systems and Inverse Problems Seminar |
DH 3rd floor SR |
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Thu, 29/01/2009 11:00 |
Jamshid Derakhshan (Oxford) |
Advanced Logic Class |
SR1 |
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Thu, 29/01/2009 12:00 |
Vicky Hoskins (Oxford) |
Junior Geometry and Topology Seminar |
SR1 |
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Thu, 29/01/2009 12:30 |
Richard Norton (University of Oxford) |
OxPDE Lunchtime Seminar |
Gibson 1st Floor SR |
| Modelling the behaviour of light in photonic crystal fibres requires solving 2nd-order elliptic eigenvalue problems with discontinuous coefficients. The eigenfunctions of these problems have limited regularity. Therefore, the planewave expansion method would appear to be an unusual choice of method for such problems. In this talk I examine the convergence properties of the planewave expansion method as well as demonstrate that smoothing the coefficients in the problem (to get more regularity) introduces another error and this cancels any benefit that smoothing may have. | |||
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Thu, 29/01/2009 14:00 |
Dr Martin Lotz (Oxford University and City University of Hong Kong) |
Computational Mathematics and Applications |
Comlab |
| This talk is concerned with the probabilistic behaviour of a condition number C(A) for the problem of deciding whether a system of n homogeneous linear inequalities in m unknowns has a non-zero solution. In the case where the input system is feasible, the exact probability distribution of the condition number for random inputs is determined, and a sharp bound for the general case. In particular, for the expected value of the logarithm log C(A), an upper bound of order O(log m) (m the number of variables) is presented which does not depend on the number of inequalities. The probability distribution of the condition number C(A) is closely related to the probability of covering the m-sphere with n spherical caps of a given radius. As a corollary, we obtain bounds on the probability of covering the sphere with random caps. | |||
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Thu, 29/01/2009 14:30 |
Xiuping Su (Bath) |
Representation Theory Seminar |
L3 |
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Thu, 29/01/2009 16:00 |
Roger Heath-Brown (Oxford) |
Number Theory Seminar |
L3 |
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Thu, 29/01/2009 16:30 |
Dave Smith (Birmingham) |
Differential Equations and Applications Seminar |
DH 1st floor SR |
| Sperm cells have been an archetype for very low Reynolds number swimming since the pioneering work of Gray & Hancock in the 1950s. However, there are fundamental questions regarding the swimming and function of mammalian, and particularly human sperm, that are unanswered, and moreover scientific and technological developments mean that for the first time, answering these questions is now possible. I will present results of our interdisciplinary work on two topics: (1) the relatively famous problem of 'surface accumulation' of sperm, and (2) characterising the changes to the flagellar beat that occur in high viscosity liquids such as cervical mucus. The approach we use combines both mathematical modelling and high speed imaging experiments. I will then discuss areas we are currently developing: quantifying the energy transport requirements of sperm, and understanding chemotaxis - the remarkable ability of human sperm to 'smell' lily of the valley perfume, which may be important in fertilisation. | |||
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Thu, 29/01/2009 17:00 |
David Bew (Oxford) |
Logic Seminar |
L3 |
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Fri, 30/01/2009 10:00 |
Emmanuelle Marquis (Oxford / Dept. of Materials) |
Industrial and Interdisciplinary Workshops |
DH 1st floor SR |
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Fri, 30/01/2009 14:15 |
Damir Filipovic (Vienna Institute of Finance) |
Nomura Seminar |
DH 1st floor SR |
| This paper provides a unifying approach for valuing contingent claims on a portfolio of credits, such as collateralized debt obligations (CDOs). We introduce the defaultable (T; x)-bonds, which pay one if the aggregated loss process in the underlying pool of the CDO has not exceeded x at maturity T, and zero else. Necessary and sufficient conditions on the stochastic term structure movements for the absence of arbitrage are given. Background market risk as well as feedback contagion effects of the loss process are taken into account. Moreover, we show that any ex- ogenous specification of the volatility and contagion parameters actually yields a unique consistent loss process and thus an arbitrage-free family of (T; x)-bond prices. For the sake of analytical and computational efficiency we then develop a tractable class of doubly stochastic affine term structure models. | |||
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Fri, 30/01/2009 14:30 |
Prof. Andy Woods (University of Cambridge.) |
Mathematical Geoscience Seminar |
DH 3rd floor SR |
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Fri, 30/01/2009 16:30 |
Athanasios Tsanas (Oxford University) |
Junior Applied Mathematics Seminar |
DH 3rd floor SR |
| The circulatory system is the most important and amongst the most complicated mechanisms in the human body. Consisting of the heart, the arteries and the veins, it is amply aided by a variety of mechanisms aiming to facilitate adequate perfusion of the body tissues at the appropriate pressure. On this talk I am focusing on the development of a computational model which relates patient specific factors (age, gender, whether someone is an athlete/smokes etc) and their effects on different vascular regions which ultimately determine the arterial pressure and the cardiac output. | |||
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Mon, 02/02/2009 12:00 |
Maxime Gabella (Oxford) |
String Theory Seminar |
L3 |
| We use generalized complex geometry to study the AdS/CFT correspondence in type IIB string theory. | |||
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Mon, 02/02/2009 14:15 |
Professor Hans Föllmer |
Stochastic Analysis Seminar |
Oxford-Man Institute |
| We discuss some connections between various notions of rationality in the face of uncertainty and the theory of convex risk measures, both in a static and a dynamic setting. | |||
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Mon, 02/02/2009 14:15 |
Gabriele Mondello (Imperial) |
Geometry and Analysis Seminar |
L3 |
| Open Riemann surfaces and the Weil-Petersson Poisson structure | |||
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Mon, 02/02/2009 15:45 |
Panos Papozoglou (Oxford) |
Topology Seminar |
L3 |
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Mon, 02/02/2009 15:45 |
Professor Hong-Quan Li (Fudan University) |
Stochastic Analysis Seminar |
Oxford-Man Institute |
| In this talk, we give the asymptotics estimates for the heat kernel and its gradient estimates on H-type groups. Moreover, we get gradient estimates for the heat semi-group. | |||
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Mon, 02/02/2009 16:00 |
Timothy Trudgian (Mathematical Institute Oxford) |
Junior Number Theory Seminar |
SR1 |
| This second 'problem sheet' of the term includes a proof of Jensen's Theorem for the number of zeroes of an analytic function in a disc, the usefulness of which is highlighted by an application to the Riemann zeta-function. | |||
