Mathematics Department

Operator Algebras and Dynamics Seminar

Fall 2016

All talks are from 3:45-4:45 p.m. in the Seminar room, unless otherwise specified.

  • Dec
  • TBD
    Van Cyr
    Bucknell University
    Time: 03:45 PM
  • Nov
  • TBA
    Peter Nandori
    University of Maryland
    Time: 03:45 PM
  • Oct
  • Unique Expectations and Pseudo-Expectations for Abelian C*-inclusions
    Vrej Zarikian
    United States Naval Academy
    Time: 03:45 PM
  • Oct
  • Pattern Formation and Fluctuations in Complex Networks
    Jason Hindes
    Naval Research Laboratory
    Time: 03:45 PM

    View Abstract

    Networks form the backbone of complex communication systems ranging from computer and social networks to swarming sensor arrays. Much attention in recent years has focused on determining how the connectivity of such networks affects the types of behavior they can produce. However, many networks of interest operate in noisy environments and fluctuate due to random internal effects, both of which can cause sudden transitions from one network state to another. In this talk, I will survey the dynamics of several well known processes, focusing on swarm pattern formation and epidemic spreading, and discuss recent advances in understanding noise-induced pathways between distinct network states using large fluctuation theory.
  • Oct
  • Using Maths to Understand the Transmission of Infectious Diseases
    Luis Mier-y-Terab
    Johns Hopkings Bloomberg School of Public Health, Naval Research Lab
    Time: 03:45 PM
  • Sep
  • Metric on regular languages using topological entropy
    Kelly Yancey
    Institute for Defense Analyses - Center for Computing Sciences
    Time: 03:45 PM

    View Abstract

    A problem that has emerged in computer science is determining the similarity between regular languages. We will represent a regular language by a deterministic finite automata (a directed graph with some marked data) and then use ideas from symbolic dynamics to develop a metric between the languages. We will also discuss other distances based on the classical Jaccard distance and how they are related to the topological entropy of a regular language. There will be no prior knowledge of automata theory assumed.
  • Aug
  • Character Rigidity for Lattices in Lie Groups
    Darren Creutz
    Location: CH320
    Time: 03:45 PM

    View Abstract

    Characters on groups (positive definite conjugation-invariant functions) arise naturally both from probability-preserving actions (the measure of the set of fixed points) and unitary representations on finite factors (the trace); the classical theory of characters is the first step in the classification of finite simple groups and culminates in the Peter-Weyl theorem for compact groups. I will present the results of J. Peterson and myself that the only characters on lattices in semisimple groups are the left-regular character and the classical characters. This is in actuality operator-algebraic superrigidity for lattices, answering a question of Connes. The main idea is to bring dynamics into the operator-algebraic picture; the second half of the talk will focus on the ergodic-theoretic ideas of contractiveness and the Poisson boundary and how these ideas lead to operator-algebraic results.
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