The closure of a set A of vertices of an infinite graph G is defined as the set of vertices of G which cannot be finitely separated from A. A subset A of Y(G) is dispersed if it is finitely separated from any ray of G. It is shown that the closure of any dispersed set A of an infinite connected grap
On finite fixed sets in infinite graphs
β Scribed by H.A. Jung
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 762 KB
- Volume
- 131
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
β¦ Synopsis
An automorphism
of a graph X is called a translation of X if it fixes no finite non-empty set of vertices of X. It is shown that a group G of automorphisms of the connected graph X fixes a finite non-empty set of vertices or ends of X if and only if any two translations of X in G have a common fixed end. Applications and refinements are discussed.
π SIMILAR VOLUMES
An \((m, n)\)-separator of an infinite graph \(\Gamma\) is a smallest finite set of vertices whose deletion leaves at least \(m\) finite components and at least \(n\) infinite components. It is shown that a vertex of \(\Gamma\) of finite valence belongs to only finitely many \((0,2)\)-separators. Va
## Abstract Let __K__ be a cardinal. If __K__ Ο~0~, define K:= __K__. Otherwise, let __K__ := __K__ + 1. We prove a conjecture of Mader: Every infinite __K__βconnected graph __G__ = (__V, E__) contains a set __S__ β __V__ with |__S__| = |__V__| such that __G/S__ is __K__βconnected for all __S__β __
For every positive integer c , we construct a pair G, , H, of infinite, nonisomorphic graphs both having exactly c components such that G, and H, are hypomorphic, i.e., G, and H, have the same families of vertex-deleted subgraphs. This solves a problem of Bondy and Hemminger. Furthermore, the pair G
Hajnal, A. and N. Sauer, Cut-sets in infinite graphs and partial orders. Discrete Mathematics 117 (1993) 113-125. The set S c V(U) is a cut-set of the vertex v of a graph 9 if v is not adjacent to any vertex in S and, for every maximal clique C of Q, ({v} u S) n C # 0. S is a cut-set of the element
## Abstract For a graph __A__ and a positive integer __n__, let __nA__ denote the union of __n__ disjoint copies of __A__; similarly, the union of β΅~0~ disjoint copies of __A__ is referred to as β΅~0~__A__. It is shown that there exist (connected) graphs __A__ and __G__ such that __nA__ is a minor o