Gjesteforelesninger og seminarer - Side 32

Pietro De Poi (Udine), gives the Seminar in Algebra and Algebraic Geometry:

A Severi type theorem on surfaces in P^6

Kristian Ranestad, UiO, gives the Seminar in Algebra and Algebraic Geometry:

Modular curves VI

Prof. Dr. Alois Gisler (ETH Zurich, RiskLab Switzerland) holds a seminar with the title "On the Development of the Swiss Solvency Test"

Prof. Dr. Alois Gisler (ETH Zurich, RiskLab Switzerland) holds a seminar with the title "The Reserve Risk of the Chain-Ladder Reserving Method from a New Perspective"

Réamonn Ó Buachalla (IMPAN) will give a talk with title: Noncommutative Kähler structures on quantum homogeneous spaces

Abstract:

Building on the definition of a noncommutative complex structure for a general algebra A, I will introduce the notion of a noncommutative Kähler structure for A. In the special case where A is a quantum homogeneous space, I show that many of the fundamental results of classical Kähler geometry follow from the existence of such a structure: Hodge decomposition, Serre duality, the Hard Lefschetz theorem, the Kähler identities, and collapse of the Frölicher spectral sequence at the first page. We then apply these results to Heckenberger and Kolb's differential calculus for quantum projective space, and show that they have cohomology groups of at least classical dimension. Time permitting, I will also discuss the relationship of this work to Connes proposal to study positive Hochschild cocycles as a starting point for noncommutative complex geometry, and Fröchlich, Grandjean, and Recknagel's definition of a Kähler spectral tuple.

Eduard Ortega, NTNU, will give a talk with title: Cuntz-Krieger uniqueness theorems

Abstract: I will make a little survey about Cuntz-Krieger uniqueness theorems and how they help to the study of the ideal structure of the rings to which one can apply them. In certain classes of (C*-)algebras this is described as topologically freeness or condition (L). However they are important classes of rings for which are not known Cuntz-Krieger type theorems. I will present a class of rings, that generalize Leavitt path algebras and Passman crossed products, for which I can totally characterize the Cuntz-Krieger uniqueness theorem.

Parameter-robust finite element discretization and its preconditioning for Biot's consolidation model in poroelasticity

Erik Bédos will give a talk with title: On the Fourier-Stieltjes algebra of a C*-dynamical system

Abstract: When G is a discrete group, its Fourier-Stieltjes algebra B(G) may be described as the set of coefficient functions associated with unitary representations of G on Hilbert spaces. In a similar way, if Sigma=(A, G, alpha, sigma) is a unital discrete twisted C*-dynamical system, one may let the Fourier-Stieltjes algebra B(Sigma) consist of the functions from G x A into A that arise as coefficient functions of equivariant representations of Sigma on Hilbert A-modules. We will explain how B(Sigma) may be organized as an algebra with conjugation, and show that it may be represented as completely bounded multipliers on the full crossed product C*(Sigma). (This is also known to be true for the reduced crossed product). This is part of an ongoing project with Roberto Conti (Rome).

Arvid Siqveland, Høgskolen i Buskerud og Vestfold, gives the Seminar in Algebra and Algebraic Geometry:

Modular curves V

These are the fifth and and the sixth lectures given by Anders Hansen (Cambridge Univ. and UiO) on Compressed sensing - Theory and Applications.

These are the third and fourth lectures given by Anders Hansen (Cambridge Univ. and UiO) on Compressed sensing - Theory and Applications.

These are the first two of six 45-min. lectures given by Anders Hansen (Cambridge Univ. and UiO) on Compressed sensing - Theory and Applications.

Fredrik Meyer, UiO, gives the Seminar in Algebra and Algebraic Geometry:

Modular curves IV

Olav Breivik (Dept. of Math., UiO ) gives a seminar in room 107, 1st floor N.H. Abels House at 14:15 March 17th:  Bycatch of juvenile cod in the Barents Sea shrimp fishery

Arne B. Sletsjøe, UiO, gives the Seminar in Algebra and Algebraic Geometry:

Modular curves III

Sam Sanders, Ghent and Munich, will give a lecture with the tittle

On the contingency of predicativism.

Franz Luef (NTNU) will give  a talk with title "Sigma-models solitons on noncommutative spaces"

Abstract: Results from time-frequency analysis and Gabor analysis allow the construction of new classes of sigma-model solitons over the Moyal plane and over noncommutative tori, taken as source spaces, with a target space made of two points. A natural action functional leads to self-duality equations for projections in the source algebra. Solutions, having non-trivial topological content, are constructed via suitable Morita duality bimodules. This is joint work with L. Dabrowski and G. Landi.

 

John Dagsvik ( Statistics Norway ) gives a seminar in room 107, 1st floor N.H. Abels House at 14:15 March 10th:  How Does the Temperature Vary over Time?  Evidence on the Stationary and Fractal  Nature of Temperature Fluctuations

Bartosz K. Kwaśniewski (University of Southern Denmark, Odense) will talk on: Topological aperiodicity for product systems of C*-correspondences

Abstract:We introduce a semigroup of multivalued maps dual to a product system of $C^*$-correspondences over an Ore semigroup. Under a certain aperiodicity condition on the dual semigroup we obtain a uniqueness theorem and a simplicity criterion for the associated Cuntz-Pimsner algebra. These results generalize similar statements for crossed products by groups (R. J. Archbold, J. S. Spielberg) and Exel’s crossed products (R. Exel, A. Vershik). They also give interesting conditions for topological higher rank graphs, and apply to the new Cuntz $C^*$-algebra $\mathcal{Q}_\mathbb{N}$ arising from the `$ax+b$'-semigroup over natural numbers. (Based on joint work with Wojciech Szymański.)

Geir Ellingsrud, UiO, gives the Seminar in Algebra and Algebraic Geometry:

Modular curves I

Adam P.W. Sørensen will talk on Nuclear dimension of UCT Kirchberg algebras

Abstract: Nuclear Dimension is a regularity property for C*-algebras that is based on the type of properties currently being taught in Topics in Operator Algebras. We will go over the definition and motivation and discuss known results.

Kasper Christensen ( Nofima, Ås and  Aarhus university ) gives a seminar in room 107, 1st floor N.H. Abels House at 14:15 February 24th:  Mining for new product ideas.

Atanas Iliev, Seoul National University, gives the Seminar in Algebra and Algebraic Geometry:

Fano manifolds - old and new