Visiting addressUllevål Stadion Sognsveien 77B
Arvid Siqveland (HBV), gives the Seminar in Algebra and Algebraic Geometry:
K3 surfaces seminar: Endomorphism fields and Mumford–Tate groups
Abstract: In this follow-up talk, we shall review the results on the structure of KMS states from the case studies of - the ax+b semigroup over the natural numbers (Laca-Raeburn and Brownlowe-an Huef-Laca-Raeburn), - integer dilation matrices (Laca-Raeburn-Ramagge), - self-similar actions (Laca-Raeburn-Ramagge-Whittaker), and - Baumslag-Solitair monoids (Clark-an Huef-Raeburn) from the perspective of the boundary quotient diagram for the respective right LCM semigroups. We will also discuss (to some extent) similarities and differences of the proofs among these cases.
Thore Egeland (NMBU) will give a seminar in the lunch area, 8th floor Niels Henrik Abels hus at 14:15.
Emanuela Rosazza Gianin (University of Milano-Bicocca) gives a lecture with the title: Time-consistency for cash-subadditive risk measures
Christian Bender (Saarland University) gives a lecture with the title: Discretizing Malliavin calculus
Abstract: For the ax+b semigroup over the natural numbers, which is known to be part of a quasi-lattice ordered group, Laca and Raeburn considered its Nica-Toeplitz algebra and its Cuntz-Nica-Pimsner algebra, with a special appeal to nice presentations by generators and relations as well as the structure of KMS states for a natural dynamics. Shortly thereafter, Brownlowe-an Huef-Laca-Raeburn showed that there are two intermediate quotients between the Nica-Toeplitz algebra and the Cuntz-Nica-Pimsner algebra that exhibit interesting structural properties, especially with regards to KMS states. Since then, analogous quotients have been considered (partly in disguise) in a growing list of case studies on the KMS state structure, e.g. for dilation matrices, self-similar actions, and Baumslag-Solitair monoids. Somewhat surprisingly, all these case studies can be viewed from the perspective of semigroup C*-algebras of right LCM semigroups, and in this talk, I shall describe a unifying perspective on such boundary quotient diagrams. Thereby several questions concerning the general structure of right LCM semigroups are raised.
Let X=Spec(R) be a smooth affine variety and let Y be a closed subvariety corresponding to an ideal I in R. Finding a set of generators for I is in general a very hard problem, even in the case where X is an affine space over a field k. However, an easy application of Nakayama’s lemma shows that the number n of generators of I is at least the number m of generators of its conormal bundle and at most m+1. We will show how to actually determine when n=m using homotopical and cohomological methods, answering in particular a long standing conjecture of Murthy.
Coffee/Tea/Biscuit from 14.00
Fredrik Meyer (UiO), gives the Seminar in Algebra and Algebraic Geometry:
K3 surfaces V: Hodge structures
Dirk Hesse (Data Scientist at Intelligent Communication) will give a seminar in the lunch area, 8th floor Niels Henrik Abels hus at 14:15.
David Ruiz Baños (IMUB, University of Barcelona) gives a talk with the title: "On the regularity of densities of Itô-type processes via stochastic control"
M. Sc. Hanna Marta Zdanowicz ved Matematisk institutt vil forsvare sin avhandling for graden ph.d.:
Pricing and hedging in energy markets with weather factor risk
M.Sc. Hanna Marta Zdanowicz ved Matematisk institutt avholder prøveforelesning over oppgitt emne: "Malliavin calculus and applications in Finance".
Atanas Iliev, Seoul National University, gives the Seminar in Algebra and Algebraic Geometry:
Verra 3-folds and EPW quartics
Salvador Ortiz-Latorre (University of Oslo) is giving his inaugural lecture with the title: High order weak approximation of SDEs
This will be a colloqium-style talk, with pictures, about the classifying spaces and automorphism groups of manifolds, and the relation to surgery theory and algebraic K-theory.
Andrea Hofmann (HBV) gives the Seminar in Algebra and Algebraic Geometry:
Minimal resolutions for projective models of K3 surfaces in rational normal scrolls
Literature used in the seminar are selected chapters in the book «K3 Projective Models in Scrolls» by Trygve Johnsen and Andreas Leopold Knutsen.
Abstract: As has been observed by many authors, the Drinfeld double of the q-deformation of a compact Lie group can be regarded as a quantization of the complexification of the original Lie group. Using this point of view, I will discuss irreducible unitary representations of these Drinfeld doubles.
Kostiantyn Ralchenko (Taras Shevchenko National University of Kyiv) gives a talk with the title: A generalisation of the fractional Brownian field based on non-Euclidean norms
Yuliya Mishura (Taras Shevchenko National University of Kyiv) gives a lecture with the title: What can happen between two self-similarities?
Geir Ellingsrud (UiO), gives the Seminar in Algebra and Algebraic Geometry:
Projective models of K3-surfaces II
The seminar takes place in the seminar room on the 9th floor of the computer science building.
Abstract: We discuss a way of constructing noncommutative projective manifolds as inductive and projective limits, generalizing the so-called Berezin quantization for ordinary compact Kähler manifolds. We first review the physical motivation for Berezin quantization and then discuss how the restriction to commutative manifolds limits the use of this quantization. We will also outline how our more general construction appears naturally in the study of the long-time limit of open quantum systems.
Ingrid Hobæk Haff (UiO, Dept. of mathematics) will give a seminar in the lunch area, 8th floor N.H. Abel's House at 14:15.
Hyperbolic-Elliptic models for two-phase flow in porous media