Events - Page 39

The Lattice Boltzmann Method and its application in modeling of physiological  flows

Adam Sørensen (UiO) will give a talk with title: Almost commuting matrices

Abstract: Two matrices A,B are said to almost commute if AB is close to BA (in a suitable norm). A question of Halmos, answered by Lin, asks if two almost commuting self-adjoint matrices are always close to two exactly commuting self-adjoint matrices. We will survey what is known about this and similar questions, and report on recent work with Loring concerning how the questions change if we look at real rather than complex matrices.

Kristan Ranestad (Dept. of Math, UiO) gives a seminar in room 107, 1st floor N.H. Abels House at 14:15 Tuesday October 14th. Algebra og statistics: Phylogenetic models from an algebraic geometric viewpoint

Victor Haughton, Professor of Radiology at the University of Wisconsin

and Adjunct Research Scientist at Simula Research Laboratory

Ørnulf Borgan (Department of Mathematics,UiO) gives a seminar

in room 107, 1st floor N.H. Abels House at 14:15 Tuesday September 23rd:

Using cumulative sums of martingale residuals for model checking in nested case-control studies  

Abstract: We show that the discrete duals of the so called free orthogonal quantum groups have the completely contractive approximation property, analogous to the free groups. The proof relies on the structure of representation categories of these quantum groups, on the C*-algebraic structure of SUq(2), and on the free product techniques of Ricard and Xu. This talk is based on joint work with Kenny De Commer and Amaury Freslon.

Welcome to the conference on Stochastics of Environmental and Financial Economics. The conference will bring together leading researchers in the fields of stochastic analysis and finance to discuss recent developments and challenges with an edge towards energy, environmental and financial markets.

The conference is organized by the Center of Advanced Studies (CAS), Stochastics of Environmental and Financial Economics. Scientific organizers: Fred Espen Benth and Giulia Di Nunno (UiO).

Abstract: Independence has been introduced as a regularity property for pairs of commuting injective group endomorphisms of a discrete abelian group with finite cokernel by Joachim Cuntz and Anatoly Vershik. We discuss various characterisations of this regularity property and show how the statements need to be adjusted when removing the restrictions that the group has to be abelian and that the cokernels have to be finite. Somewhat surprisingly, this leads to the concept of *-commutativity. This property is defined for pairs of commuting self-maps of an arbitrary set. As an examples of *-commutativity, we explain a construction related to the Ledrappier shift and indicate how one obtains examples for independent group endomorphisms from this construction. If time permits, we will point out instances where the two notions have been readily used to obtain C*-algebraic results. Roughly speaking, both notions are designed to give rise to pairs of doubly commuting isometries, which significantly simplifies the analysis of the constructed C*-algebras. This is particularly useful when one tries to generalise results from the case of a single transformation to an action generated by finitely many transformations.

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.

Three-dimensional instability of solitary water waves

Per A. Mykland (The University of Chicago) og Lan Zhang (University of Illinois at Chicago) give a seminar in  Auditorium 4, Vilhelm Bjerknes house, at 14:15, Tuesday June 17th: Assessment of Uncertainty in High Frequency Data: The Observed Asymptotic Variance

If B is a sub-Hopf algebra of the mod 2 Steenrod algebra, the category of B-modules has subcategories of modules local or colocal with respect to certain Margolis homologies, and corresponding localization and colocalization functors. The Picard groups of these subcategories are sufficient to detect the Picard group of the whole category and contain modules of geometric interest. General results obtained along the way allow us to begin to attack the analogous questions for E(2) and A(2)-modules. Applications include better descriptions of polynomial algebras as modules over the Steenrod algebra, and of the values of certain generalized cohomology theories on the classifying spaces of elementary abelian groups.   

Diana Domanska (University of Silesia) gives a seminar in  Auditorium 4, Vilhelm Bjerknes house, at 14:15, Tuesday June 10th:

Forecasting methods.

Abstract: We talk about independent resolutions for dynamical systems on totally disconnected spaces. Building on earlier work by Cuntz, Echterhoff and Li that allows one to compute the K-theory of totally disconnected systems that admit a so called independent invariant regular basis, we show how any totally disconnected dynamical system admits a resolution of such systems, which in some cases allows for K-theory computations. Based on work by me and X. Li.

Marco Matassa (UiO) will give a talk with title: On dimension and integration for spectral triples associated to quantum groups

Abstract: Abstract: I will discuss some aspects of the notions of spectral dimension and non-commutative integral in the context of modular spectral triples. I will focus on two examples: the modular spectral triple for SU_q(2) introduced by Kaad and Senior and the family of spectral triples for quantum projective spaces introduced by D'Andrea and Dąbrowski.

Jens Kaad (Trieste), will give a talk with title "Joint torsion line bundles of commuting operators"

Abstract:

In this talk I’ll associate a holomorphic line bundle to any commuting tuple of bounded operators on a Hilbert space. The transition functions for this bundle are given by the joint torsion which compares determinants of Fredholm complexes. The joint torsion is an invariant of the second algebraic K-group of the Calkin algebra (bounded operators modulo trace class operators). The main step is to prove that the transition functions for the joint torsion line bundle are indeed holomorphic. This is carried out by studying the Quillen-Freed holomorphic determinant line bundle over the space of Fredholm complexes. In particular I will construct a holomorphic section of a certain pull-back of this bundle. The talk is based on joint work with Ryszard Nest.

Magnus D. Norling will give a talk with title "Universal coefficient theorem in KK-theory". This presentation is part of the final act of the course on "The Baum-Connes conjecture and KK-theory".

Bas Jordans will give a talk with title  "Higson's characterization of KK-theory". This presentation is  part of the final act of the course on "The Baum-Connes conjecture and Kasparov's KK-theory".

Steffen Grønneberg (BI Norwegian Business School), gives a seminar in  Auditorium 4, Vilhelm Bjerknes house, at 14:15, Tuesday May 27th:

Econometric inference theories and multiple use of the same data

Professor Harry Zheng (Imperial College, London) holder et seminar med tittelen: Existence and Construction of Smooth Solutions to HJB Equations and Applications 

Professor Yaozhong Hu (University of Kansas) holder et seminar med tittelen: Density convergence for some nonlinear Gaussian stationary sequences

Flow induced vibration (FIV) is a recent discipline in Flow Assurance which focuses on the piping and equipment vibrations caused by the internal flow of gas, oil and/or water in subsea production systems (SPS). Those vibrations may cause fatigue failure at weak spots in the piping such as welds and tees. Due to recent incidents and ever-increasing production rates and velocities, FIV is now considered as a major limiting factor in the design and operation of SPS. Based on real cases and ongoing projects, this presentation provides an introduction to the following aspects: fluid-structure interaction mechanism, fatigue mechanism, design requirements for SPS, analysis tools and vibration monitoring techniques.