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SUMMARY:Decomposition of multiple coverings of the plane - Dömötör Pál
 völgyi (Rényi Institute\, Budapest)
DTSTART:20150219T160000Z
DTEND:20150219T170000Z
UID:TALK58101@talks.cam.ac.uk
CONTACT:Andrew Thomason
DESCRIPTION:A collection of planar sets is called an m-fold covering if ev
 ery point is contained in at least m sets. Pach proposed in 1980 to study 
 which coverings can be decomposed into two coverings\, i.e.\, for which co
 llections the sets can be colored with red and blue such that both the red
  and the blue sets form a 1-fold covering. We survey related results and d
 isproof one of his conjectures. We show that for every m there exists an m
 -fold covering of the plane with unit disks that does not decompose into t
 wo coverings.
LOCATION:MR12
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