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UID:20251103T023141EST-8023wGb7ju@132.216.98.100
DTSTAMP:20251103T073141Z
DESCRIPTION:Title: An introduction to Borel chromatic numbers.\n\nThe Borel
  chromatic number – introduced by Kechris\, Solecki\, and Todorcevic (1999
 ) – generalizes the chromatic number on finite graphs to definable graphs 
 on topological spaces. We will see examples of graphs with chromatic numbe
 r 2 which cannot be colored in a Borel way with less than 3 colors (or eve
 n any finite number of colors). Many interesting examples of Borel graphs 
 also arise from the continuous or Borel action of a finitely generated gro
 up on a topological space. I will explain the proof that a Borel graph wit
 h bounded degree k can always be colored using k+1 colors in a Borel way. 
 Finally I will discuss the problem of characterizing the Borel graphs with
  finite Borel chromatic number.\n
DTSTART:20180912T190000Z
DTEND:20180912T200000Z
LOCATION:Room 1104\, Burnside Hall\, CA\, QC\, Montreal\, H3A 0B9\, 805 rue
  Sherbrooke Ouest
SUMMARY:Yann Pequignot (9IÖÆ×÷³§Ãâ·Ñ)
URL:/mathstat/channels/event/yann-pequignot-mcgill-uni
 versity-289487
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