Current Lectures and Events
16.04.2019 um 16:15 Uhr in 69/125:
Alexandros Grosdos Koutsoumpelias (Universität Osnabrück)
Combinatorial methods for algebraic problems in graphical models
Graphical models encode causal relations among random variables and find a range of applications in statistics. In the case of Gaussian random variables, the covariance matrix associated to the graph consists of rational functions in a polynomial ring. Goal of this talk is to shed light on algebraic questions related to the covariance matrix, such as finding its ideal or studying the fibers of the corresponding map. We present three combinatorial tools to do this, namely treks on graphs, graph decomposition and nested determinants.
23.04.2019 um 16:15 Uhr in 69/125:
Marcin Wnuk (Universität Osnabrück)
Negative Dependence in Numerical Integration and Discrepancy Theory
Intuitively, a randomized point set in a d-dimensional unit cube is said to be negatively dependent if the points tend not to cluster. In my talk I will present a few notions of negative dependence, as well as their applications: it turns out that negatively dependent point sets yield good quadrature nodes, and in some sense (measured by the so-called discrepancy) are highly regular.
In the end I will discuss concrete constructions of negatively dependent point sets.