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Annual Program Seminars

During each Annual Thematic Program, several seminars are offered. Talks will include graduate-level lectures as well as seminars covering various topics related to the theme.

  • Measurable Equidecompositions via Combinatorics and Group Theory

    Oleg Pikhurko, University of Warwick
    September 18, 2014 2:00 PM - 3:00 PM
    Lind 305 [Map]

    Abstract

    Let n>2. We show that every two subsets of S^{n-1} (resp. two bounded subsets of R^n) of the same measure and with non-emtpy interior can be equidecomposed using pieces that are measurable. Joint work with Lukasz Grabowski and Andras Mathe.
  • Infinite Geometric Graphs and Properties of Metrics

    Jeannette Janssen, Dalhousie University
    September 25, 2014 2:00 PM - 3:00 PM
    Lind 305 [Map]

    Abstract

    If the random graph model G(n,p) is extended to a countably infinite set, we obtain a unique graph (up to isomorphism), known as the Rado graph R. With my co-author Anthony Bonato, we aimed to take a similar approach in a geometric setting. Given a countable set of points in a metric space (R^n, d), two points are made adjacent with probability p if their distance is at most 1. For certain metrics, this leads to a unique isomorphism type. Moreover, the graph has a deterministic construction. For other metrics, we obtain infinitely many isomorphism types. The dichotomy hangs on a particular rounding property of metrics.
  • Nordhaus-Gaddum Sum Problems for Tree-width and Colin de Verdière Parameters

    Leslie Hogben, Iowa State University
    October 9, 2014 2:00 PM - 3:00 PM
    Lind 305 [Map]

    Abstract

    A Nordhaus-Gaddum sum problem for a graph parameter is to determine a tight lower or upper bound for the sum of the parameter evaluated on a graph and on its complement. This talk will survey Nordhaus-Gaddum sum results and open questions for tree-width, the Colin de Verdière type parameters µ and ν, and related parameters (all of the parameters discussed will be defined).

    The tight lower bound for tree-width is tw(G)+tw(Ḡ) ≥ |G|- 2: It has been conjectured that µ(G) + µ(Ḡ) ≥ |G| ≥ - 2 and ν(G) + ν(Ḡ) ≥ |G| - 2: Partial results and other evidence for these conjectures will be discussed.

    Upper and lower bounds on the Nordhaus-Gaddum upper multiplier b, where ν(G) + ν(Ḡ) ≤ bν|G| for all G, will also be discussed, together with questions about bounds on upper multipliers for the other parameters.
  • TBA

    Zoltan Furedi, Hungarian Academy of Sciences (MTA)
    October 16, 2014 2:00 PM - 3:00 PM
    Lind 305 [Map]

    Abstract forthcoming.

  • TBA

    Jerrold Griggs, University of South Carolina
    October 23, 2014 2:00 PM - 3:00 PM
    Lind 305 [Map]

    Abstract forthcoming.

  • TBA

    Patricia Hersh, North Carolina State University
    October 30, 2014 2:00 PM - 3:00 PM
    Lind 305 [Map]

    Abstract forthcoming.

  • TBA

    Prasad Tetali, Georgia Institute of Technology
    November 6, 2014 2:00 PM - 3:00 PM
    Lind 305 [Map]

    Abstract forthcoming.

  • TBA

    Penny Haxell, University of Waterloo
    November 20, 2014 2:00 PM - 3:00 PM
    Lind 305 [Map]

    Abstract forthcoming.

  • TBA

    Ryan Martin, Iowa State University
    December 4, 2014 2:00 PM - 3:00 PM
    Lind 305 [Map]

    Abstract forthcoming.

Previous Annual Seminars

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