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arXiv · 2109.02729

Improved Upper Bound on the Linear Turán Number of the Crown

Willem Fletcher
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Abstract

A linear $3$-graph is a set of vertices along with a set of edges, which are three element subsets of the vertices, such that any two edges intersect in at most one vertex. The crown, $C$, is a specific $3$-graph consisting of three pairwise disjoint edges, called jewels, along with a fourth edge intersecting all three jewels. For a linear $3$-graph, $F$, the linear Turán number, $ex(n,F)$, is the maximum number of edges in any linear $3$-graph that does not contain $F$ as a subgraph. Currently, the best known bounds on the linear Turán number of the crown are \[ 6 \Big \lfloor \frac{n-3}{4}\Big \rfloor \leq ex(n, C) \leq 2n. \] In this paper, the upper bound is improved to $ex(n,C) < \frac{5n}{3}$.

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Willem Fletcher. 2021-09-06. Improved Upper Bound on the Linear Turán Number of the Crown. https://arxiv.org/abs/2109.02729

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