Tuza's Conjecture is Asymptotically Tight for Dense Graphs

Autor: Baron, Jacob D., Kahn, Jeff
Rok vydání: 2014
Předmět:
Zdroj: Combinatorics, Probability and Computing (2016) 25, 645-67
Druh dokumentu: Working Paper
DOI: 10.1017/S0963548316000067
Popis: An old conjecture of Zs. Tuza says that for any graph $G$, the ratio of the minimum size, $\tau_3(G)$, of a set of edges meeting all triangles to the maximum size, $\nu_3(G)$, of an edge-disjoint triangle packing is at most 2. Here, disproving a conjecture of R. Yuster, we show that for any fixed, positive $\alpha$ there are arbitrarily large graphs $G$ of positive density satisfying $\tau_3(G)>(1-o(1))|G|/2$ and $\nu_3(G)<(1+\alpha)|G|/4$.
Comment: Changes in version 2: fixed typos; clarified introduction slightly; clarified discussion of "gain/loss at an edge" at the bottom of p. 13. Results unchanged. 22 pages
Databáze: arXiv