Visiting addressUllevål Stadion Sognsveien 77B
Dr. Alexander Schnurr (TU Dortmund) holder et seminar med tittelen: A Canonical Way to Derive Properties of Lévy-Type Processes
Professor Massimo Fornasier, from the Technical University of Munich, is visiting the department /CMA. This is his second lecture.
Professor Massimo Fornasier, from the Technical University of Munich, is visiting the department /CMA and he will give two guest lectures.
Jørgen Vold Rennemo, Imperial College, gives the Seminar in Algebra and Algebraic Geometry:
Derived categories of intersections of quadrics
Professor Yaozhong Hu (University of Kansas) holder et seminar med tittelen: Stochastic heat equations with general multiplicative Gaussian noises: Hölder continuity and intermittency
John Christian Ottem, Cambridge, gives the Seminar in Algebra and Algebraic Geometry:
Om to formodninger av Hartshorne
Martin Jullum (Department of Mathematics, UiO), gives a seminar in Auditorium 4, Vilhelm Bjerknes house, at 14:15, Tuesday March 4th:
Parametric or Nonparametric: The Focused Information Criterion Approach
Jan Martin Nordbotten (University of Bergen) will give a talk about
Finite volume methods for elasticity and poro-elasticity
Abstract: We introduce a new class of cell-centered finite volume methods for elasticity and poro-elasticity. This class of discretization methods has the advantage that the mechanical discretization is fully compatible (in terms of grid and variables) to the standard cell-centered finite volume discretizations that are prevailing for commercial simulation of multi-phase flows in porous media.
For a specific variant of the proposed discretization, we give an overview of a convergence proof in the setting of isotropic elasticity, and address from a theoretical perspective the issues of a discrete Korn's inequality and robustness with respect to locking. Furthermore, we give numerical results for both structured and unstructured grids for both elasticity and poro-elasticity. The talk concludes with an application to simulation of fractured and fracturing porous media.
Torstein Nilssen (Universitetet i Oslo) holder et seminar med tittelen: Malliavin differentiability for a class of SDE's in Hilbert spaces.
A continuation of the previous talk.
Magnus Landstad will give a talk with title: Quantum groups from almost matched pairs of groups - the groupoid approach
Abstract: If G is a locally compact group with two closed subgroups H,K s.t. G=HK, then (H,K) is called a matched pair of subgroups. The construction of a quantum group from such a pair goes back a long time. We shall look at the more general case where the subgroups are almost matched (the complement of HK in G has measure 0), then a groupoid approach to the construction is very useful and many formulas are obtained for free.
I shall start with explaining the concepts needed (quantum groups, groupoids, etc) and then how the groupoid is constructed. Finally we shall look at the special case where G has a compact open subgroup.
This is joint work with A. Van Daele.
Dongho Chae (Chung-Ang University, Korea) will give a seminar talk entitled
On the self-similar blow-up for the compressible Euler equations
Abstract: The problem of ﬁnite time blow-up/global regularity of the 3D incompressible Euler equations is an outstanding problem in mathematical ﬂuid mechanics. On the other hand, the scenario of self-similar type blow-up is a natural candidate of blow-ups in various nonlinear partial differential equations such as the porous medium equation and the nonlinear Schrödinger equations. We also mention that for the closely related incompressible Navier-Stokes equations the question of self-similar blow-up was raised by J. Leray in 1930, and was negatively answered by J. Necas, M. Ruzicka and V. Sverak in 1996. In this talk we present the progress of study during the last several years on the self-similar blow-up for the Euler equations.
Johanna Ridder (University of Oslo) will give a talk about
Analysis of a finite difference method for two-dimensional incompressible magnetohydrodynamics
Abstract: We consider the magnetohydrodynamics equations for a viscous incompressible resistive fluid in two dimensions. For these equations we analyse a semi-discrete finite difference scheme that is based on a staggered grid and is energy preserving. We show an a priori H^1-bound and the convergence of the scheme.
Geir Ellingsrud, UiO, gives the Seminar in Algebra and Algebraic Geometry
Twisted cubic curves on cubic fourfolds
Professor B. Rajeev (India Statistical Institute, Bangalore) holder et seminar med tittelen: The Monotonicity Inequality on Hermite-Sobolev spaces.
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
Atanas Iliev, Seoul National University, gives the Seminar in Algebra and Algebraic Geometry:
EPW sextics and Hibert squares of K3 surfaces
Antoine Julien (NTNU) will give a talk with title: Tiling spaces, groupoids and K-theory
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).
Kristian Ranestad, UiO, gives the Seminar in Algebra and Algebraic Geometry:
On the local cactus rank of a form
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.
Risk measures are set to quantify in terms of assets/money the amount of financial risk associated to a certain financial position. The purposes for such evaluations are many and interesting both from the investors perspectives and regulators. As example, these evaluations are important to quantify the amount of reserve that financial institutions, such as banks or insurance companies, have to set aside as hedging guarantee. In the recent years large attention is given towards convex and coherent risk measures.
A series of 10 lectures will be held by Prof. Giacomo Scandolo, Department of Mathematics, University of Verona (Italy), visiting scholar at our department.
The course is suggested to Master and PhD students in the area of Stochastic Analysis, Insurance, and Risk as well as practitioners in the area.
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