Turán numbers of some complete degenerate hypergraphs

Series
Graph Theory Seminar
Time
Tuesday, October 5, 2021 - 11:00am for 1 hour (actually 50 minutes)
Location
Skiles 005
Speaker
Xiaofan Yuan – Georgia Institute of Technology – xyuan@gatech.eduhttps://people.math.gatech.edu/~xyuan62/
Organizer
Anton Bernshteyn

Please Note: Note the unusual time!

Let $K^{(r)}_{s_1,s_2,\cdots,s_r}$ be the complete $r$-partite $r$-uniform hypergraph and $ex(n, K^{(r)}_{s_1,s_2,\cdots,s_r})$ be the maximum number of edges in any $n$-vertex $K^{(r)}_{s_1,s_2,\cdots,s_r}$-free $r$-uniform hypergraph. It is well-known in the graph case that $ex(n,K_{s,t})=\Theta(n^{2-1/s})$ when $t$ is sufficiently larger than $s$. We generalize the above to hypergraphs by showing that if $s_r$ is sufficiently larger than $s_1,s_2,\cdots,s_{r-1}$ then $$ex(n, K^{(r)}_{s_1,s_2,\cdots,s_r})=\Theta\left(n^{r-\frac{1}{s_1s_2\cdots s_{r-1}}}\right).$$ This is joint work with Jie Ma and Mingwei Zhang.