Nowhere-zero 4-flows and cycle double covers
β Scribed by Cun-Quan Zhang
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 572 KB
- Volume
- 154
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
β¦ Synopsis
In this paper, we obtained some necessary and sufficient conditions for a graph having 5, 6and 7-cycle double covers, etc. We also provide a few necessary and sufficient conditions for a graph admitting a nowhere-zero 4-flow. With the aid of those basic properties of nowhere-zero 4flow and the result about 5-cycle double cover, we are able to prove that each 2-edge-connected graph with one edge short of admitting a nowhere-zero 4-flow has a 5-cycle double cover which is a generalization of a theorem due to Huck and Koch01 (JCTB, 1995) for cubic graphs.
π SIMILAR VOLUMES
## Abstract It is shown that the edges of a simple graph with a nowhereβzero 4βflow can be covered with cycles such that the sum of the lengths of the cycles is at most |__E__(__G__)| + |__V__(__G__)| β3. This solves a conjecture proposed by G. Fan.
Let G be a 2-edge-connected simple graph with order n. We show that if IV(G)l 5 17, then either G has a nowhere-zero 4-flow, or G is contractible to the Petersen graph. We also show that for n large, if Iβ¬(G)J L (' 2 17) + 34, then either G has a nonwhere-zero 4-flow, or G can be contracted to the P
In [J Combin Theory Ser B, 26 (1979), 205-216] , Jaeger showed that every graph with 2 edge-disjoint spanning trees admits a nowhere-zero 4-flow. In [J Combin Theory Ser B, 56 (1992), 165-182], Jaeger et al. extended this result by showing that, if A is an abelian group with |A| = 4, then every gra
## Abstract Jensen and Toft 8 conjectured that every 2βedgeβconnected graph without a __K__~5~βminor has a nowhere zero 4βflow. Walton and Welsh 19 proved that if a coloopless regular matroid __M__ does not have a minor in {__M__(__K__~3,3~), M\*(__K__~5~)}, then __M__ admits a nowhere zero 4βflow.