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Mathematics > Combinatorics

Title: Generalized Tuza's conjecture for random hypergraphs

Abstract: A celebrated conjecture of Tuza states that in any finite graph the minimum size of a cover of triangles by edges is at most twice the maximum size of a set of edge-disjoint triangles. For an $r$-uniform hypergraph ($r$-graph) $G$, let $\tau(G)$ be the minimum size of a cover of edges by $(r-1)$-sets of vertices, and let $\nu(G)$ be the maximum size of a set of edges pairwise intersecting in fewer than $r-1$ vertices. Aharoni and Zerbib proposed the following generalization of Tuza's conjecture: $$ \text{For any $r$-graph $G$, $\tau(G)/\nu(G) \leq \lceil(r+1)/2\rceil$.} $$
Let $H_r(n,p)$ be the uniformly random $r$-graph on $n$ vertices. We show that, for $r \in \{3, 4, 5\}$ and any $p = p(n)$, $H_r(n,p)$ satisfies the Aharoni-Zerbib conjecture with high probability (i.e., with probability approaching 1 as $n \rightarrow \infty$). We also show that there is a $C < 1$ such that, for any $r \geq 6$ and any $p = p(n)$, $\tau(H_r(n, p))/\nu(H_r(n, p)) \leq C r$ with high probability. Furthermore, we may take $C < 1/2 + \varepsilon$, for any $\varepsilon > 0$, by restricting to sufficiently large $r$ (depending on $\varepsilon$).
Comments: 32 pages including references and appendix; minor corrections throughout the article; accepted to SIAM J. Discrete Math
Subjects: Combinatorics (math.CO)
MSC classes: 05D15, 05D40
Cite as: arXiv:2204.04568 [math.CO]
  (or arXiv:2204.04568v2 [math.CO] for this version)

Submission history

From: Abdul Basit [view email]
[v1] Sat, 9 Apr 2022 23:44:18 GMT (27kb)
[v2] Tue, 14 May 2024 13:11:23 GMT (26kb)

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