### Conferences - Seminars

22MAY

10:15-11:15
CM 1 113

## Topology Seminar: On Mackey 2-functors

(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, ...
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By Ivo Dell'Ambrogio (Université de Lille)

22MAY

13:45-14:45
MA A1 12

## Del Pezzo fibrations in positive characteristic

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 ...
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By Andrea Fanelli (Universität Düsseldorf)

22MAY

15:15-16:15
PH H3 31

## Test vectors for some ramified representations of $GL(2)$

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 ...
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By Vinayak Vatsal (University of British Columbia)

22MAY

16:15
MA A3 31

## Surrogate modelling for uncertainty quantification in engineering applications

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 ...
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By Prof. Bruno SUDRET, Institute of Structural Engineering, ETH Zürich

23MAY

16:15-17:15
MA A3 30

## Diagonal Cubic Forms and Manin's conjecture

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).
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By Fabian Dehnert (Universität Göttingen)

24MAY

13:00-14:00
MA A3 30

## Strong ergodicity versus spectral gap for group actions on measure spaces

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 ...
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By Cyril Houdayer (Université de Paris-Sud)

24MAY

15:15-16:00
MA A1 10

## Learning determinantal point processes

Statistics seminar
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By Prof. Philippe Rigollet, MIT