Abstract
We introduce a natural extension of the vertex degree to ends. For the cycle space C(G) as proposed by Diestel and Kühn [4, 5], which allows for infinite cycles, we prove that the edge set of a locally finite graph G lies in C(G) if and only if every vertex and every end has even degree. In the same way we generalise to locally finite graphs the characterisation of the cycles in a finite graph as its 2-regular connected subgraphs.
Similar content being viewed by others
References
Th. Andreae: Über maximale Systeme von kantendisjunkten unendlichen Wegen in Graphen, Math. Nachr. 101 (1981), 219–228.
R. Diestel: The cycle space of an infinite graph, Comb., Probab. Comput. 14 (2005), 59–79.
R. Diestel: Graph Theory (3rd ed.), Springer-Verlag, 2005.
R. Diestel and D. Kühn: On infinite cycles I, Combinatorica 24(1) (2004), 69–89.
R. Diestel and D. Kühn: On infinite cycles II, Combinatorica 24(1) (2004), 91–116.
R. Diestel and D. Kühn: Topological paths, cycles and spanning trees in infinite graphs; Eurp. J. Combinatorics 25 (2004), 835–862.
G. A. Dirac: Some theorems on abstract graphs, Proc. London Math. Soc. 2 (1952), 69–81.
R. Halin: A note on Menger’s theorem for infinite locally finite graphs, Abh. Math. Sem. Univ. Hamburg 40 (1974), 111–114.
D. W. Hall and G. L. Spencer: Elementary Topology, John Wiley, New York, 1955.
F. Laviolette: Decompositions of infinite graphs: Part II — Circuit decompositions, J. Comb. Theory, Ser. B 94(2) (2005), 278–333.
W. Mader: Homomorphieeigenschaften und mittlere Kantendichte von Graphen, Math. Ann. 174 (1967), 265–268.
C. St. J. A. Nash-Williams: Decomposition of graphs into two-way infinite paths, Can. J. Math. 15 (1963), 479–485.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Bruhn, H., Stein, M. On end degrees and infinite cycles in locally finite graphs. Combinatorica 27, 269–291 (2007). https://doi.org/10.1007/s00493-007-2149-0
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00493-007-2149-0