Reminder: this is today. Please note the unusual time and location.
Misha.
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On 2022-06-02 09:09, Mykhaylo Tyomkyn wrote:
Dear all,
This week there is no noon lecture.
The last noon lecture of the semester will be on Tuesday, 7 June, and will be given by Jindrich Zapletal, the talk details are given below. Please be aware of the unusual day, time and meeting room.
Best regards, Misha.
Coloring graphs on Euclidean spaces Jindrich Zapletal University of Florida / Czech Academy of Sciences June 7, 2022, 15:00 in S5
Abstract For n>0, let Gn be the graph connecting points in Rn of rational Euclidean distance. In ZFC, these graphs all have countable chromatic number. I proved that for every n>0, it is consistent with choiceless set theory that Gn has countable chromatic number while Gn+1 does not, showing that the coloring problem grows in difficulty with n. The proof depends on certain finite combinatorial features of Rn, and the talk will concentrate on these.