Hypergraph families with bounded edge cover or transversal number
The transversal number \(\tau\), packing number \(\nu\), covering number \(\rho\), and strong stability number \(\alpha\) of hypergraphs are studied. A family F of finite hypergraphs is \(\tau\)-bound (\(\rho\)-bound) if there exists a binding function f such that \(\tau\) (H)\(\leq f(\nu(H))\) (\(\rho\) (H)\(\leq f(\alpha(H)))\) for all \(H\in F\). The existence of a binding function in case of various \(\tau\)-bound (\(\rho\)-bound) is given. It is essentially based on the exclusion of octahedron graphs. Hypergraph versions of the clique color theorem of \textit{A. Gyárfás} [Infinite finite sets, Colloq. Honour Paul Erdős, Keszthely 1973, Colloq. Math. Soc. János Bolyai 10, 801-816 (1975; Zbl 0307.05111)] are presented. Further results concern Helly hypergraphs with \(C_ 4\)-free line-graph, c-forest hypergraphs, strong Helly hypergraphs, boxes, and polyominoes (cf. the paper of \textit{C. Berge}, \textit{C. C. Chen}, \textit{V. Chvátal} and \textit{C. S. Seow} [Combinatorica 1, 217-224 (1981; Zbl 0491.05048)]).
scientific article; zbMATH DE number 3847440