Oliver Janzer: On the Turán number of graphs with minimum degree 3

Abstract: 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 100 dollars for a counterexample. We disprove the conjecture by finding, for any $\epsilon>0$, a 3-regular bipartite graph H with $ex(n,H)=O(n^{4/3+\epsilon})$.

Zoom link: https://zoom.us/j/2961946869