Tidligere arrangementer - Side 42

In 1980 R. W. Thomason published a proof that CAT, the category of small categories, is a proper closed model category that is Quillen equivalent to SSet, the category of simplicial sets, with the standard model structure defined by Quillen. D-C Cisinski has since corrected the proof of left properness by replacing the central term of Dwyer morphism - a class of morphisms that Thomason believed to be the cofibrations - with a rough analogue in CAT of the NDR-pairs. The cofibrations, then, which are all retracts of Dwyer morphisms, are really the NDR-pair analogues. I will go through the main parts of Thomason's argument, incorporating Cisinski's adjustment, point out Thomason's mistake and here and there use more recent terminology from M. Hovey's book Model Categories. Towards the end I'll compare Thomason's method with modern, standardized ways of confirming a cofibrantly generated (closed) model structure, like the necessary and sufficient conditions listed in Hovey's Model Categories (thm. 2.1.19) and transferring a model structure across an adjunction by using Kan's lemma on transfer and similar results 

Antoine Julien (NTNU) will give a talk with title: Tiling spaces, groupoids and K-theory

Abstract:

 In this talk, I will describe how spaces, groupoids and C*-algebras can be associated with aperiodic tilings. In some cases, it is possible to describe the structure of the groupoid combinatorially in terms of augmented Bratteli diagrams. (joint work with Jean Savinien) Time permitting, I will expose a strategy for computing the K-theory of the tiling algebra in terms of the K-theory of AF-algebras (work in progress).

David Ruiz Baños (University of Oslo) holder et seminar med tittelen: On the regularity of densities of SDE's. A classical solution to the stochastic transport equation

Jeonghun J. Lee (Aalto University, Helsinki) will give a talk about

On unified analysis of mixed methods for elasticity with weakly symmetric stress.

Abstract: We introduce a framework to construct and analyze mixed finite elements for elasticity with weakly symmetric stress. The framework is based on a connection between mixed methods for elasticity and mixed methods for Stokes equations. We show that some new finite elements can be obtained from it with optimal error bounds.

Rajib Dutta (University of Oslo) will give a seminar talk on

Operator splitting methods for Benjamin-Ono (BO) equation

Abstract: We consider the BO equation which describes one-dimensional internal waves in deep water. In this talk, we show that both Godunov and Strang splitting methods converge with the expected rates if the initial data are sufficiently smooth. We also present a proof of convergence of a fully discrete finite difference scheme for this equation.  

Takuya Takeishi, University of Tokyo, will give a talk with title: Bost-Connes system for local fields of characteristic zero

Abstract: The Bost-Connes system, which describes the relation between quantum statistical mechanics and class field theory, was first constructed by Bost and Connes for the rational field, and generalized for arbitrary number fields by the contribution of many researchers. In this talk, we will introduce a generalization of the Bost-Connes sysmtem for local fields of characteristic zero, and introduce some properties.

Prof. Dr. Stefan Ankirchner (University of Bonn) holder et seminar med tittelen: The Skorokhod embedding problem for homogeneous diffusions and applications to stopping contests

The 14th Annual Winter School of eVITA/SINTEF will be held January 19-24th 2014 in Geilo. The topic for the 2014 school is Big data challenges to modern statistics, with several internationally renowned experts giving a series of lectures on the subject.  Read more on the SINTEF website of the winter school (external link).  

The logic seminar will take place in B63 in NHA on Thursdays from 10.15 to 12.00.

The program is tentative. There are free slots in the program. Contact Dag Normann for suggestions or questions.

Hanna Zdanowicz (Univeritetet i Oslo) holder et seminar med tittelen: Pricing of energy spread options by Fourier transform

Giuseppe Coclite, University of Bari.

In this lecture we consider a model for the harvesting of marine  resources, described by a parabolic equation. Since the cost functionals have sublinear growth with respect to the  pointwise intensity of fishing effort, optimal solutions are in general measure-valued. For the control problem, we prove the existence of optimal strategies. The results were obtained in collaboration with Professor Mauro  Garavello.  

A General Framework for Implementing Conservation-law Solvers

Dr. Benjamin Holcblat (BI Norwegian Business School) holder et seminar med tittelen: A Classical Moment-Based Approach with Bayesian Properties: Econometric Theory and Empirical Evidence from Asset Pricing

Jukka Lempa (Oslo and Akershus University college of applied sciences) holder et seminar med tittelen: Resolvent-techniques for multiple exercise problems

Judith Packer, University of Colorado (Boulder), will give a talk with title "Noncommutative solenoids and their projective modules"

Abstract: ``Noncommutative solenoids" are certain twisted group $C^*$-algebras, where the groups in question are countably infinitely generated; these algebras can also be generated as direct limits of rotation algebras.  From examining the range of the trace of the $K_0$-groups of the noncommutative solenoids, their finitely generated projective modules can be constructed. We also discuss a way to construct Morita equivalence bimodules between noncommutative solenoids that goes back to work of M. Rieffel, with the new wrinkle of $p$-adic analysis appearing. This work is joint with F. Latr\'emoli\'ere.

Professor Madan L. Puri (Indiana University) holder et seminar med tittelen: Asymptotic Normality, Rates of Convergence, and Large Deviation Probabilities for a Broad Class of Statistics.

Abstract: We will begin by reviewing and constructing power operations in the familiar setting of chain complexes. In stable homotopy, these operations help distinguish different geometric objects. These operations are also the residue of a rich homotopical structure. We will also define such structure and explain its role in stable homotopy theory. Specifically, we will consider what structure on a filtration might give rise to power operations in the associated spectral sequence, if time allows. This first talk will be accessible to graduate students.    Such power operations also act on the homotopy of highly structured ring spectra. We will compute these operations on relative smash products using the Kunneth spectral sequence. We will interpret the homotopy of these relative smash products and the algebra of operations in terms of different realizations of highly structured DGAs. We will also discuss the relation to the relevant notion of cotangent complexes. 

Professor Paul Ehling (BI Norwegian Business School): Asset Prices and Portfolio Choice with Learning from Experience

Paul Krühner (University of Oslo) holder et seminar med tittelen: On uniqueness of Markov processes described by a symbol.

Bas Jordans (UiO) will give a talk with title: Real dimensional spaces in noncommutative geometry

Abstract:

In noncommutative geometry geometric spaces are given by spectral triples. In this talk we consider a generalisation of these spectral triples to semifinite spectral triples. In analogy to the classical case it is possible to construct the product of two semifinite spectral triples. We will construct this product and derive properties thereof. Also we will describe for each z\in(0,\infty) a semifinite spectral triple which can be considered as having dimension z. As an application these "z-dimensional" semifinite triples will be used for two regularisation methods in physics.

Dr. Ujjwal Koley from University of Würzburg, is going to talk about Operator splitting methods for Korteweg de-Vries (KdV) equation

Marcus Eriksson (Universitet i Oslo): Green certificates in the Nord Pool market