Visiting addressUllevål Stadion Sognsveien 77B
Professor Massimo Fornasier, from the Technical University of Munich, is visiting the department /CMA. This is his second lecture.
M. Sc. Sven Haadem ved Matematisk institutt vil forsvare sin avhandling for graden ph.d.: Stochastic Control and Optimal Stopping for Non-Markov Processes with Infinite Horizon and Related Topics
Professor Massimo Fornasier, from the Technical University of Munich, is visiting the department /CMA and he will give two guest lectures.
M. Sc. Sven Haadem ved Matematisk institutt avholder prøveforelesning over oppgitt emne: "Stable Distributions".
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
M. Sc. Nathalie Støer ved Matematisk institutt vil forsvare sin avhandling for graden ph.d.: Reuse of Controls from Nested Case-Control Studies in Cancer Research
M. Sc. Nathalie Støer ved Matematisk institutt avholder prøveforelesning over oppgitt emne: "Confounding, mediation and colliding in epidemiological data".
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).
Abstract: In this talk, my goal is to give an introduction to some of the mathematics behind quasicrystals. Quasicrystals were discovered in 1982, when Dan Schechtmann observed a material which produced a diffraction pattern made of sharp peaks, but with a 10-fold rotational symmetry. This indicated that the material was highly ordered, but the atoms were nevertheless arranged in a non-periodic way.These quasicrystals can be defined by certain aperiodic tilings, amongst which the famous Penrose tiling. What makes aperiodic tilings so interesting--besides their aesthetic appeal--is that they can be studied using tools from many areas of mathematics: combinatorics, topology, dynamics, operator algebras... While the study of tilings borrows from various areas of mathematics, it doesn't go just one way: tiling techniques were used by Giordano, Matui, Putnam and Skau to prove a purely dynamical statement: any Z^d free minimal action on a Cantor set is orbit equivalent to an action of Z.
NB: Coffee/tea and cookies will served from 14.00-14.25 in the rest area of the 7th floor in NH Abel's House, as usual. Note that the colloquium talk will be held in Aud 2 VB from 14.30.
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.