2017. 11. 17. 14:15 - 2017. 11. 17. 15:45
ELTE Déli épület – 3.607
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Esemény típusa: szeminárium
Szervezés: Külsős
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Leírás

We show an asymptotically tight result for the lower bound on  the number of copies of $K_{2,t}$ graphs in balanced bipartite graphs, in terms of the number of edges,   if the excess over the extremal number ex_bi( n+n, K_{2,t}) is at least of order n\sqrt{n}.

We also point out that the applied construction  yields a good bound on certain bipartite Ramsey numbers as well. 

Finally, we present a novel construction of the projective plane over a finite field via the solutions of a Vandermonde-type matrix-equality.