Tidligere arrangementer - Side 41
QOMBINE seminar talks by Delphine Martres (University of Oslo) and Alexander Müller-Hermes (University of Oslo)
Prof. Julian Caskel, from Folkwang University of the Arts, will speak at RITMO's Seminar Series.
Nakajima quiver varieties are a class of combinatorially defined moduli spaces generalising the Hilbert scheme of points in the plane, defined with the aid of a quiver Q (directed graph) and a fixed framing dimension vector f. In the 90s Nakajima used the cohomology of these varieties (in fixed cohomological degrees, and for fixed f) to construct irreducible lowest weight representations of the Kac-Moody Lie algebras associated to the underlying graph of Q. Since the action is via geometric correspondences, the entire cohomology of these quiver varieties forms a module for the same Kac-Moody Lie algebras, suggesting the question: what is the decomposition of the entire cohomology into irreducible lowest weight representations?
In this talk I will explain that this question is somehow not the right one. I will introduce the BPS Lie algebra associated to Q, a generalised Kac-Moody Lie algebra associated to Q, which contains the usual one as its cohomological degree zero piece. The entire cohomology of the sum of Nakajima quiver varieties for fixed Q and f turns out to have an elegant decomposition into irreducible lowest weight modules for this Lie algebra, with lowest weight spaces isomorphic to the intersection cohomology of certain singular Nakajima quiver varieties. This is joint work with Lucien Hennecart and Sebastian Schlegel Mejia.
Finding the optimal shape is a vivid research area and has a wide range of applications, e.g., in fluid mechanics and acoustics. Moreover, there is also a close link to image registration and image segmentation. In this talk, we consider shape optimization tasks as optimal control problems that are constrained by partial differential equations. From this perspective, state-of-the-art methods can be motivated by the choice of the metric on the set of admissible shapes. Moreover, a new approach for density based topology optimization is presented in the setting of Stokes flow. It is based on classical topology optimization and phase field approaches, and introduces a different way to relax the underlying infinite-dimensional mixed integer problem. We give a theoretically founded choice of the relaxed problems and present numerical results. Moreover, in order to show the potential of the new approach, we do a comparison to a classical approach. (joint work with Michael Ulbrich and Franziska Neumann)
I en tid med fokus p? funksjon, m?lstyring og instrumentell nytte, faller danning lett i bakgrunnen. Hvorfor er det s?nn?
A tropical curve is a graph embedded in R^2 satisfying a number of conditions. Mikhalkin's celebrated correspondence theorem establishes a correspondence between algebraic curves on a toric surface and tropical curves. This translates the difficult question of counting the number of algebraic curves through a given number of points to the question of counting tropical curves, i.e. certain graphs, with a given notion of multiplicity through a given number of points which can be solved combinatorially. To get an invariant count, real rational algebraic curves are counted with a sign, the Welschinger sign and there is a real version of the correspondence theorem. Furthermore, Marc Levine defined a generalization of the Welschinger sign that allows to get an invariant count of algebraic curves defined over an arbitrary base field. For this one counts algebraic curves with a certain quadratic form.
In the talk I am presenting work in progress joint with Andrés Jaramillo Puentes in which we provide a version Mikhalkin's correspondence theorem for an arbitrary base field, that is a correspondence between algebraic curves counted with the above mentioned quadratic form and tropical curves counted with a quadratic enrichment of the multiplicity. Then I will explain how to use this quadratic correspondence theorem to do the count of algebraic curves over an arbitrary base field.
C*-algebra seminar talk by Lucas Hataishi (University of Oslo)
Juan Christian Pellicer (University of Oslo)
Associate professor Aaron Hess and professor Jens Kjeldsen will give a seminar to the Text & Rhetoric Research Seminar, on a theme of great importance to rhetorical studies as well as to life in general: ethos.
Associate professor Aaron Hess will give a seminar to the Text & Rhetoric Research Seminar, on the theme ?participatory approaches to rhetoric?.
By José Pablo Vázquez-Medina from the University of Bekerley
What’s in a ‘verb’? Is there some lexical content which marks a word as a ‘verb’ or ‘noun’, or even a single level of analysis at which we could define them? Evidence from multiple fields of linguistics suggests not.
Jan Eivind Myhre, Professor Emeritus at the Department of Archaeology, Conservation and History, University of Oslo.
Following Givental, enumerative mirror symmetry can be stated as a relation between genus zero Gromov-Witten invariants and period integrals. I will talk about a relative version of mirror symmetry that relates genus zero relative Gromov-Witten invariants of smooth pairs and relative periods. Then I will talk about how to use it to compute the mirror proper Landau-Ginzburg potentials of smooth log Calabi-Yau pairs.
Department seminar. Inga Deimen is an assistant professor at the University of Arizona. She will present the paper: "Strategic information transmission in the employment relationship" (written with Andreas Blume).
I will go through my PhD work at DTU. It is about the development of a fully-nonlinear finite difference based potential flow solver which imposes all of the fluid boundaries via an immersed boundary method. The convergence and stability of this approach is first established for various linear and nonlinear wave propagation problems. When it comes to the wave-body interaction problem, cautious attention is paid to the intersection point between free surface and body surface, and a scheme which meets the accuracy and stability requirements best is picked from several proposals. With the scheme introduced in this paper, piston type wave maker and forced heaving cylinder cases with high oscillation frequency have been simulated successfully.
Internal solitary waves (ISWs) are underwater waves of great amplitude moving horizontally in the layered ocean. The waves induce a velocity field which is felt both at the ocean surface, throughout the entire water column, and at the bottom. When of great amplitude, the waves induce a vortex wake in the bottom boundary layer behind the wave and transport water in the vertical direction displacing, e.g., sediments from the bottom. A fundamental mechanism in the ocean ecosystem is the vertical mixing and movement of particles, e.g., biological materials. In this talk, we present numerical simulations of ISWs of depression and of large amplitude by replicating a laboratory experiment. Furthermore, we discuss the dynamics of ISW-sediment interactions and illustrate particle movements, trajectories, and particle distribution in the water column under the influence of ISWs of large amplitude.
Quentin Noraz, Postdoctoral Fellow at Rosseland Centre for Solar Physics, University of Oslo.
Guest lecture. Dr. Andreas Ravndal Kost?l will hold a guest lecture with the title "Workforce Analytics: Understanding Labor Demand".
The digital guest lecture is open to the public, and staff and students are welcome to attend.
“The idea of world-centred education is first of all meant to highlight that educational questions are fundamentally existential questions, that is questions about our existence ‘in’ and ‘with’ the world, natural and social, and not just our existence with ourselves” (Biesta, 2021, pp. 90-91)
Guest lecture. Dr. Adrien Vigier will hold a guest lecture about "Moral hazard".
The guest lecture is open to the public, and staff and students are welcome to attend.
Felleskollokvium by Heidi Sandaker, Head of the Norwegian Center for CERN-related research (NorCC)