19.10.2018 um 16:15 Uhr in 69/125:
Prof. Dr. Yuri Manin (Max Planck Institute for Mathematics Bonn)
Cosmology and Big Bang (joint with M. Marcolli)
It is well known that the so called Bianchi IX spacetimes with SO(3)--symmetry in a neighbourhood of the Big Bang exhibit a chaotic behaviour of typical trajectories in the backward movement of time. This behaviour (Mixmaster Model of the Universe) can be encoded by the shift of two--sided continued fractions.
Exactly the same shift encodes the sequences of intersections of hyperbolic geodesics with purely imaginary axis in the upper complex half--plane, that is geodesic flow on an appropriate modular surface.
We suggest that this effect can be understood in a quantum mechanical way, as a transition from a pure imaginary time "at the moment" of Big Bang to inverse cosmologicaltemperature of cooling Universe.
24.10.2018 um 17:15 Uhr in 69/125:
Dr. Matthias Wendt (Universität Osnabrück)
Oriented Schubert Calculus: Using Quadratic Forms to Count Subspaces
30.10.2018 um 16:15 Uhr in 69/125:
Markus Wageringel (Universität Osnabrück)
23.10.2018 um 14:15 Uhr in 69/E15:
Maria Yakerson (Universität Duisburg-Essen)
How to encode transfers in motivic homotopy theory
Voevodsky’s approach to constructing the (derived) category of motives starts with introducing so called presheaves with transfers. Later Calmès and Fasel added extra data of quadratic forms to this construction, by considering presheaves with Milnor-Witt transfers. We will show that these transfers are examples of a more general construction of E-transfers, defined for any motivic ring spectrum E. We will also discuss relation of E-transfers with framed transfers, and some consequences for understanding the category of E-modules.
This is joint work with Elden Elmanto, Marc Hoyois, Adeel Khan and Vladimir Sosnilo