Crowns in Linear $3$-Graphs of Minimum Degree $4$

  • Alvaro Carbonero
  • Willem Fletcher
  • Jing Guo
  • András Gyárfás
  • Rona Wang
  • Shiyu Yan


A 3-graph is a pair H = (V, E) of sets, where elements of V are called points or vertices and E contains some 3-element subsets of V , called edges. A 3-graph is called linear if any two distinct edges intersect in at most one vertex.
There is a recent interest in extremal properties of 3-graphs containing no crown, three pairwise disjoint edges and a fourth edge which intersects all of them. We show that every linear 3-graph with minimum degree 4 contains a crown. This is not true if 4 is replaced by 3.

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