Article
Keywords:
connectivity; Steiner tree; internally disjoint Steiner tree; packing; pendant tree-connectivity, lexicographic product
Summary:
For a connected graph $G=(V,E)$ and a set $S \subseteq V(G)$ with at least two vertices, an $S$-Steiner tree is a subgraph $T = (V',E')$ of $G$ that is a tree with $S \subseteq V'$. If the degree of each vertex of $S$ in $T$ is equal to 1, then $T$ is called a pendant $S$-Steiner tree. Two $S$-Steiner trees are {\it internally disjoint} if they share no vertices other than $S$ and have no edges in common. For $S\subseteq V(G)$ and $|S|\geq 2$, the pendant tree-connectivity $\tau _G(S)$ is the maximum number of internally disjoint pendant $S$-Steiner trees in $G$, and for $k \geq 2$, the $k$-pendant tree-connectivity $\tau _k(G)$ is the minimum value of $\tau _G(S)$ over all sets $S$ of $k$ vertices. We derive a lower bound for $\tau _3(G\circ H)$, where $G$ and $H$ are connected graphs and $\circ $ denotes the lexicographic product.
References:
[2] Hind, H. R., Oellermann, O.:
Menger-type results for three or more vertices. Congr. Numerantium 113 (1996), 179-204.
MR 1393709 |
Zbl 0974.05047
[3] Li, X., Mao, Y.:
The generalized 3-connectivity of lexicographic product graphs. Discrete Math. Theor. Comput. Sci. 16 (2014), 339-354.
MR 3223294 |
Zbl 1294.05105
[6] Yang, C., Xu, J.-M.:
Connectivity of lexicographic product and direct product of graphs. Ars Comb. 111 (2013), 3-12.
MR 3100156 |
Zbl 1313.05212