• Corpus ID: 237278451

Hypergraph Tur\'an Problems in $\ell_2$-Norm

  title={Hypergraph Tur\'an Problems in \$\ell\_2\$-Norm},
  author={J{\'o}zsef Balogh and Felix Christian Clemen and Bernard Lidick{\'y}},
There are various different notions measuring extremality of hypergraphs. In this survey we compare the recently introduced notion of the codegree squared extremal function with the Turán function, the minimum codegree threshold and the uniform Turán density. The codegree squared sum co2(G) of a 3-uniform hypergraph G is defined to be the sum of codegrees squared d(x, y)2 over all pairs of vertices x, y. In other words, this is the square of the `2-norm of the codegree vector. We are interested… 

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  • R. Baber
  • Mathematics, Computer Science
  • 2012
A number of extensions to Razborov's semidefinite flag algebra method are described, including one which can be applied in a more general setting, notably to 3-uniform hypergraphs, to get a new upper bound of 0.5615 for $\pi(K_4^3)$.