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Friday Seminar (Summer Semester 2014)

The Friday Seminar is an informal weekly seminar for

  • members of discrete mathematics group
  • students in the group
  • everybody else that is interested

Every week there is one speaker that gives a talk of one of the following kind

  • presentation of original research
  • introduction into an open problem that he/she currently works on
  • presentation of proposed plan for bachelor, master, diploma or PhD thesis
  • presentation of results from bachelor, master, diploma or PhD thesis
  • presentation of research paper that might be of interest for the group
Schedule
Seminar: Friday 14:00-15:30 1C-02 Begin: 11.4.2014

UPCOMING TALK

Friday July 25, 14:00

Kunal Dutta

On the Discrepancy of Certain Point-Capturing Hypergraphs

For a finite set X of points in the plane, a set S in the plane, and a positive integer k, we say that a k-element subset Y of X is captured by S if there is a homothetic copy S' of S such that X \cap Y = S, i.e., S contains exactly k elements from X. A k-uniform S-capturing hypergraph H = H(X,S,k) has a vertex set X and a hyperedge set consisting of all k-element subsets of X captured by S.

We study the point-capturing hypergraphs formed when S belongs to certain kinds of fat convex bodies. Using a result of Axenovich and Ueckerdt, we show that for k large enough, H is not only 2-colorable, but also has a nearly balanced 2-coloring.




Talk History

  • 2014/07/18 -- Jonathan Rollin -- Conflict-Free Colorings and Factors of Regular Graphs
  • 2014/07/11 -- Georg Osang -- The Local Chromatic Number
  • 2014/07/04 -- Andre Kündgen -- Spanning Quadrangulations of Triangulated Surfaces
  • 2014/06/27 -- Sarah Lutteropp -- On Layered Drawings of Planar Graphs
  • 2014/06/13 -- Jennifer Weidelich -- Adjacent Vertex Distinguishing Colorings
  • 2014/06/06 -- Jonathan Klawitter -- Transforming Rectangles Into Squares
  • 2014/05/30 -- Stefan Walzer -- Disjoint Induced Subgraphs of the Same Order and Size
  • 2014/05/23 -- Pascal Weiner -- Improper Colourings of Graphs
  • 2014/05/16 -- Open Discussion -- Sympossium Diskrete Mathematik 2014
  • 2014/05/02 -- Peter Stumpf -- Covering Numbers of Different Kinds
  • 2014/04/25 -- Anika Kaufmann -- Clumsy Packings of Regular Graphs Into a Complete Graph
  • 2014/04/11 -- Piotr Micek -- Lower Bounds for On-Line Graph Colorings
  • 2014/02/13 -- Yury Person -- Powers of Hamilton Cycles in Pseudorandom Graphs
  • 2014/02/07 -- Sarah Lutteropp -- On Layered Drawings of Planar Graphs
  • 2014/01/31 -- Stefan Walzer -- Tron : A Two Player Game on Graphs
  • 2014/01/24 -- Annette Karrer -- Simultaneous Embeddings of Outerplanar Graphs
  • 2014/01/17 -- Torsten Ueckerdt -- The Density of Fan-Planar Graphs
  • 2014/01/10 -- Maria Axenovich -- On Distinguishing Colorings
  • 2013/12/13 -- Fabian Stroh -- Coloring Graphs Using Topological Lemmas
  • 2013/12/06 -- Enrica Cherubini -- Coloring Mixed Hypergraphs
  • 2013/11/29 -- Jonathan Rollin -- Hamiltonicity in Sparse Graphs With High Chromatic Number
  • 2013/11/18 -- Torsten Ueckerdt -- Scattered Sets in Cocomparability Graphs