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SUMMARY:Polychromatic colouring and cover-decomposition problems in the pl
 ane - Dömötör Pálvölgyi (University of Cambridge)
DTSTART:20160526T133000Z
DTEND:20160526T143000Z
UID:TALK65480@talks.cam.ac.uk
CONTACT:Andrew Thomason
DESCRIPTION:Is it true that given a finite point set on a sphere and a set
  of halfspheres\, such that the set system that they induce on the point s
 et is a Sperner family\, we can select a subset of the points that meet ev
 ery halfsphere in at least one but at most two points?\nI don't know the a
 nswer to this question (waiting to be solved by YOU!)\, but I know that th
 e above holds in the plane if instead of halfspheres we take (pseudo)halfp
 lanes. I will talk about consequences of similar results in polychromatic 
 colouring and cover-decomposition\, and also mention several other open pr
 oblems.\n
LOCATION:MR12
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