Forthcoming Seminars

Thu, 20/05/2010
17:00 		John Campbell (Harvard University) Nomura Lecture Add to calendar Said Business School
The Changing Risks of Government Bonds
The covariance between nominal bonds and stocks has varied considerably over recent decades and has even switched sign. It has been predominantly positive in periods such as the late 1970s and early 1980s when the economy has experienced supply shocks and the central bank has lacked credibility. It has been predominantly negative in periods such as the 2000s when investors have feared weak aggregate demand and deflation. This lecture discusses the implications of changing bond risk for the shape of the yield curve, the risk premia on bonds, and the relative pricing of nominal and inflation-indexed bonds.
Thu, 20/05/2010
17:00 		Dana Scott (Carnegie Mellon/Oxford) Logic Seminar Add to calendar L3
Semilattices, Domains, and Computability
As everyone knows, one popular notion of a (Scott-Ersov) domain is defined as a bounded complete algebraic cpo. These are closely related to algebraic lattices: (i) A domain becomes an algebraic lattice with the adjunction of an (isolated) top element. (ii) Every non-empty Scott-closed subset of an algebraic lattice is a domain. Moreover, the isolated (= compact) elements of an algebraic lattice form a semilattice (under join). This semilattice has a zero element, and, provided the top element is isolated, it also has a unit element. The algebraic lattice itself may be regarded as the ideal completion of the semilattice of isolated elements. This is all well known. What is not so clear is that there is an easy-to-construct domain of countable semilattices giving isomorphic copies of all countably based domains. This approach seems to have advantages over both the so-called "information systems" or more abstract lattice formulations, and it makes definitions of solutions to domain equations very elementary to justify. The "domain of domains" also has a natural computable structure
Fri, 21/05/2010
10:00 		Professor Bob Pego (Carnegie Mellon University) OxPDE Events Add to calendar Gibson 1st Floor SR
Lecture Series: Scaling Dynamics in Aggregation Models
Clustering phenomena occur in numerous areas of science. This series of lectures will discuss: (i) basic kinetic models for clustering- Smoluchowski's coagulation equation, random shock clustering, ballistic aggregation, domain-wall merging; (ii) Criteria for approach to self-similarity- role of regular variation; (iii) The scaling attractor and its measure representation. A particular theme is the use of methods and insights from probability in tandem with dynamical systems theory. In particular there is a close analogy of scaling dynamics with the stable laws of probability and infinite divisibility.
Fri, 21/05/2010
11:15 		tba (TBA) OCCAM Special Seminar Add to calendar OCCAM Common Room (RI2.28)
OCCAM group meeting
Fri, 21/05/2010
11:30 		Industrial and Interdisciplinary Workshops Add to calendar OCCAM Common Room (RI2.28)
OCCAM group meeting
Fri, 21/05/2010
12:00 		Tim Adamo (Oxford) Twistor Workshop Add to calendar Gibson 1st Floor SR
Hopf Algebras and BCFW recursion after Kreimer
Abstract: We will review Kreimer's construction of a Hopf algebra for Feynman graphs, and explore several aspects of this structure including its relationship with renormalization and the (trivial) Hochschild cohomology of the algebra.  Although Kreimer's construction is heavily tied with the language of renormalization, we show that it leads naturally to recursion relations resembling the BCFW relations, which can be expressed using twistors in the case of N=4 super-Yang-Mills (where there are no ultra-violet divergences).  This could suggest that a similar Hopf algebra structure underlies the supersymmetric recursion relations...
Fri, 21/05/2010
12:45 		John Campell (Harvard University) Nomura Seminar Add to calendar Oxford-Man Institute
Forced Sales and House Prices"
This paper uses data on house transactions in the state of Massachusetts over the last 20 years to show that houses sold after foreclosure, or close in time to the death or bankruptcy of at least one seller, are sold at lower prices than other houses. Foreclosure discounts are particularly large on average at 27 result from poor home maintenance by older sellers, while foreclosure discounts appear to be related to the threat of vandalism in low-priced neighborhoods. After aggregating to the zipcode level and controlling for regional price trends, the prices of forced sales are mean-reverting, while the prices of unforced sales are close to a random walk. At the zipcode level, this suggests that unforced sales take place at approximately ecient prices, while forced-sales prices re ect time-varying illiquidity in neighborhood housing markets. At a more local level, however, we nd that foreclosures that take place within a quarter of a mile, and particularly within a tenth of a mile, of a house lower the price at which it is sold. Our preferred estimate of this e ect is that a foreclosure at a distance of 0.05 miles lowers the price of a house by about 1
Fri, 21/05/2010
14:15 		Nan Chen (CUHK) Nomura Seminar Add to calendar Oxford-Man Institute
A Non-Zero-Sum Game Approach to Convertible Bonds: Tax Benefit, Bankrupt Cost and Early/Late Calls
Convertible bonds are hybrid securities that embody the characteristics of both straight bonds and equities. The conflict of interests between bondholders and shareholders affects the security prices significantly. In this paper, we investigate how to use a non-zero-sum game framework to model the interaction between bondholders and shareholders and to evaluate the bond accordingly. Mathematically, this problem can be reduced to a system of variational inequalities. We explicitly derive a unique Nash equilibrium to the game. Our model shows that credit risk and tax benefit have considerable impacts on the optimal strategies of both parties. The shareholder may issue a call when the debt is in-the-money or out-of-the-money. This is consistent with the empirical findings of “late and early calls" (Ingersoll (1977), Mikkelson (1981), Cowan et al. (1993) and Ederington et al. (1997)). In addition, the optimal call policy under our model offers an explanation for certain stylized patterns related to the returns of company assets and stock on calls.  
Fri, 21/05/2010
14:30 		Professor Mike Baines and Dale Partridge (Reading) Mathematical Geoscience Seminar Add to calendar DH 3rd floor SR
Moving grids for a simple glacier model
Mon, 24/05/2010
12:00 		Djordje Minic (VirginiaTech) String Theory Seminar Add to calendar L3
String Theory and Many-Body Physics
Recent theoretical advances in string theory relate in an unexpected way the physics of gravity in certain D dimensional space-times with the dynamics of quantum field theories living on the associated (D-1) dimensional space-time boundary. This unsuspected relationship offers a remarkable new tool for dealing with some outstanding problems in condensed matter physics. In the first part of the talk I aim to explain both the intuitive and technical underpinnings of these new developments. In the second half of the talk I will present some recent results on aging in systems far from equilibrium and also some new avenues for research in condensed matter physics which involve the interplay of gauge fields, membranes and many-body systems. In particular this last work opens up an exciting possibility for fundamentally new states of condensed matter.
Mon, 24/05/2010
14:15 		Christian Litterer (Oxford) Stochastic Analysis Seminar Add to calendar Eagle House
Rough Paths on Manifolds
Mon, 24/05/2010
16:00 		Tobias Barthel (University of Oxford) Junior Number Theory Seminar Add to calendar SR1
Galois representations III: Eichler-Shimura theory
In the first half of the talk we explain - in very broad terms - how the objects defined in the previous meetings are linked with each other. We will motivate this 'big picture' by briefly discussing class field theory and the Artin conjecture for L-functions. In the second part we focus on a particular aspect of the theory, namely the L-function preserving construction of elliptic curves from weight 2 newforms via Eichler-Shimura theory. Assuming the Modularity theorem we obtain a proof of the Hasse-Weil conjecture.
Mon, 24/05/2010
17:00 		Varga kalantarov (Koç University) Partial Differential Equations Seminar Add to calendar Gibson 1st Floor SR
CANCELED
Tue, 25/05/2010
00:00 		see page events/liepowers Representation Theory Seminar Add to calendar L1
Lie powers and related topics, Second day
Tue, 25/05/2010
12:00 		Tsou Sheung Tsun Quantum Field Theory Seminar Add to calendar L3
A Tale of Two CPs

For any corrections/updates to these listings, please contact seminars [-at-] maths [dot] ox [dot] ac [dot] uk.

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