## Abstract Bonnington and Richter defined the cycle space of an infinite graph to consist of the sets of edges of subgraphs having even degree at every vertex. Diestel and KΓΌhn introduced a different cycle space of infinite graphs based on allowing infinite circuits. A more general point of view w
The cycle space of an embedded graph
β Scribed by B. Richter; H. Shank
- Publisher
- John Wiley and Sons
- Year
- 1984
- Tongue
- English
- Weight
- 258 KB
- Volume
- 8
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
β¦ Synopsis
Abstract
Let G be a connected graph with edge set E embedded in the surface β. Let GΒ° denote the geometric dual of G. For a subset d of E, let Ο__d__ denote the edges of GΒ° that are dual to those edges of G in d. We prove the following generalizations of wellβknown facts about graphs embedded in the plane.
(1) b is a boundary cycle in G if and only if Ο__b__ is a cocycle in GΒ°.
(2) If T is a spanning tree of G, then Ο(E/T) contains a spanning tree of GΒ°.
(3) Let T be any spanning tree of G and, for e Ο΅ E/T, let T(e) denote the fundamental cycle of e. Let U βͺ E/T. Then Ο__U__ is a spanning tree of GΒ° if and only if the set of face boundaries, less any one, together with the set {T(e); e Ο΅ E/(T βͺ U)} is a basis for the cycle space of G.
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## Abstract This paper considers conditions ensuring that cycleβisomorphic graphs are isomorphic. Graphs of connectivity β©Ύ 2 that have no loops were studied in [2] and [4]. Here we characterize all graphs __G__ of connectivity 1 such that every graph that is cycleβisomorphic to __G__ is also isomor