26 research outputs found
Geodetic topological cycles in locally finite graphs
We prove that the topological cycle space C(G) of a locally finite graph G is
generated by its geodetic topological circles. We further show that, although
the finite cycles of G generate C(G), its finite geodetic cycles need not
generate C(G).Comment: 1
On the homology of locally finite graphs
We show that the topological cycle space of a locally finite graph is a
canonical quotient of the first singular homology group of its Freudenthal
compactification, and we characterize the graphs for which the two coincide. We
construct a new singular-type homology for non-compact spaces with ends, which
in dimension~1 captures precisely the topological cycle space of graphs but
works in any dimension.Comment: 30 pages. This is an extended version of the paper "The homology of a
locally finite graph with ends" (to appear in Combinatorica) by the same
authors. It differs from that paper only in that it offers proofs for Lemmas
3, 4 and 10, as well as a new footnote in Section