The tacnode Riemann-Hilbert problem

The tacnode Riemann-Hilbert problem is a 4 x 4 matrix valued RH problem that appears in the description of the local behavior of two touching groups of non-intersecting Brownian motions. The same RH problem was also found by Duits and Geudens to describe a new critical regime in the two-matrix model. Delvaux gave integral representations for some of the entries of the 4 x 4 matrix. We complement this work by presenting integral representations for all of the entries. As a consequence we give an explicit formula for the Duits-Geudens critical kernel.Comment: 29 pages, 5 figure

The trace formula and the existence of PEL type Abelian varieties modulo p

We show, using the trace formula, that any Newton stratum of a Shimura variety of PEL-type of types (A) and (C) is non-empty at the primes of good reduction. Furthermore we prove conditionally the non-emptiness for Shimura data associated to odd Spin groups. Our results are conditional on Rapoport-Langlands conjecture and Arthur's conjectures on the discrete spectrum. Both these results have been announced by Arthur and Kisin in significant cases

Semantic systems and visual tools to analyze climate change communication

Given the intense attention that environmental topics such as climate change attract in news and social media coverage, key questions are how different stakeholders perceive observable threats and policy options, how public media react to new scientific insights, and how journalists present climate science knowledge to the public. This presentation will demonstrate the Web intelligence platform [1] to address these questions, including knowledge extraction and visualization techniques to explore the lexical and geospatial context of online coverage. The examples stem from the Media Watch on Climate Change [2], the Climate Resilience Toolkit [3] and the NOAA Media Watch the three applications that aggregate environmental resources from a wide range of online sources. These systems not only show the value of providing comprehensive information to the public, but also have helped to develop novel communication success metrics beyond bipolar assessments of sentiment

The Complexity of Iterated Strategy Elimination

We consider the computational complexity of the question whether a certain strategy can be removed from a game by means of iterated elimination of dominated strategies. In particular, we study the influence of different definitions of domination and of the number of different payoff values. In addition, the consequence of restriction to constant-sum games is shown