Conferences - Seminars

  10:15-11:15 CM 1 113

(Joint work with Paul Balmer.) We propose a categorification of the notion of Mackey functor for finite groups, intended to capture "higher" equivariant phenomena occurring throughout mathematics which are invisible to ordinary Mackey functors. Examples of such structures include familiar equivariant objects such as: (abelian and derived) categories of linear group representations, stable module categories, ... Read more about "Topology Seminar: On Mackey 2-functors"
By Ivo Dell'Ambrogio (Université de Lille)
  13:45-14:45 MA A1 12

In this talk, I will discuss some pathologies for the generic fibre of del Pezzo fibrations in characteristic p>0, motivated by the recent developments of the MMP in positive characteristic. The recent joint work with Stefan Schröer applies to deduce information on the structure of 3-dimensional Mori fibre spaces and answers an old question by ... Read more about "Del Pezzo fibrations in positive characteristic"
By Andrea Fanelli (Universität Düsseldorf)
  15:15-16:15 PH H3 31

Abstract: We give an explicit construction of test vectors for $T$-equivariant linear functionals on representations $\Pi$ of $GL_2$ of a local field, where $T$ is a non-split torus. Of particular interest is the case when both the representations are ramified; we completely solve this problem for principal series and Steinberg representations of $GL_2$, as well ... Read more about "Test vectors for some ramified representations of $GL(2)$"
By Vinayak Vatsal (University of British Columbia)
  16:15 MA A3 31

Abstract: Computational models are used nowadays in virtually all fields of applied sciences and engineering to predict the behaviour of complex natural or man-made systems. Those simulators allow the analyst to assess the performance of systems before actual manufacturing. They usually feature dozens of parameters and are expensive to run, even when taking full advantage ... Read more about "Surrogate modelling for uncertainty quantification in engineering applications"
By Prof. Bruno SUDRET, Institute of Structural Engineering, ETH Zürich
  16:15-17:15 MA A3 30

Abstract: We give examples of progress made in Manin's conjecture in biprojective setting using the Circle method and show how Vaughan's result for an asymptotic Formula for the sum of 8 cubes can be gerneralized to deal with bidegree (1,3). Read more about "Diagonal Cubic Forms and Manin's conjecture"
By Fabian Dehnert (Universität Göttingen)
  13:00-14:00 MA A3 30

It is well-known that for probability measure preserving (pmp) group actions, if the associated Koopman representation has spectral gap (i.e. has no almost invariant vectors), then the action is strongly ergodic (i.e. has no non-trivial almost invariant measurable subsets). The converse is however not true as demonstrated by Schmidt’s example. In this talk, I will ... Read more about "Strong ergodicity versus spectral gap for group actions on measure spaces"
By Cyril Houdayer (Université de Paris-Sud)