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* Princeton Discrete Math Seminar *
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Speaker: Oliver Janzer (ETH Zurich)
Thursday 18th November, 3:00 via Zoom.
Zoom link https://princeton.zoom.us/j/93006186024, password will be mailed to the seminar
list.
Title: Disproof of a conjecture of Erdős and Simonovits on
the Turán number of graphs with minimum degree 3
In 1981, Erdős and Simonovits conjectured that for any
bipartite graph H we have ex(n,H)=O(n^{3/2}) if and only if H is
2-degenerate. Later, Erdős offered 250 dollars for a proof and
500 dollars for a counterexample.
We disprove the conjecture by finding, for any epsilon>0, a
3-regular bipartite graph H with ex(n,H)=O(n^{4/3+epsilon}).
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Next week: Thanksgiving break. Week after: Samuel Mohr
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