TY - JOUR
T1 - 2-Factors in claw-free graphs with locally disconnected vertices
AU - An, Mingqiang
AU - Xiong, Liming
AU - Tian, Runli
N1 - Publisher Copyright:
© 2015, Institute of Mathematics of the Academy of Sciences of the Czech Republic, Praha, Czech Republic.
PY - 2015/6/26
Y1 - 2015/6/26
N2 - An edge of G is singular if it does not lie on any triangle of G; otherwise, it is non-singular. A vertex u of a graph G is called locally connected if the induced subgraph G[N(u)] by its neighborhood is connected; otherwise, it is called locally disconnected. In this paper, we prove that if a connected claw-free graph G of order at least three satisfies the following two conditions: (i) for each locally disconnected vertex v of degree at least 3 in G, there is a nonnegative integer s such that v lies on an induced cycle of length at least 4 with at most s non-singular edges and with at least s-5 locally connected vertices; (ii) for each locally disconnected vertex v of degree 2 in G, there is a nonnegative integer s such that v lies on an induced cycle C with at most s non-singular edges and with at least s-3 locally connected vertices and such that G[V (C)∩V2(G)] is a path or a cycle, then G has a 2-factor, and it is the best possible in some sense. This result generalizes two known results in Faudree, Faudree and Ryjáček (2008) and in Ryjáček, Xiong and Yoshimoto (2010).
AB - An edge of G is singular if it does not lie on any triangle of G; otherwise, it is non-singular. A vertex u of a graph G is called locally connected if the induced subgraph G[N(u)] by its neighborhood is connected; otherwise, it is called locally disconnected. In this paper, we prove that if a connected claw-free graph G of order at least three satisfies the following two conditions: (i) for each locally disconnected vertex v of degree at least 3 in G, there is a nonnegative integer s such that v lies on an induced cycle of length at least 4 with at most s non-singular edges and with at least s-5 locally connected vertices; (ii) for each locally disconnected vertex v of degree 2 in G, there is a nonnegative integer s such that v lies on an induced cycle C with at most s non-singular edges and with at least s-3 locally connected vertices and such that G[V (C)∩V2(G)] is a path or a cycle, then G has a 2-factor, and it is the best possible in some sense. This result generalizes two known results in Faudree, Faudree and Ryjáček (2008) and in Ryjáček, Xiong and Yoshimoto (2010).
KW - 2-factor
KW - claw-free graph
KW - closure
KW - locally disconnected vertex
KW - singular edge
UR - http://www.scopus.com/inward/record.url?scp=84934997110&partnerID=8YFLogxK
U2 - 10.1007/s10587-015-0177-2
DO - 10.1007/s10587-015-0177-2
M3 - Article
AN - SCOPUS:84934997110
SN - 0011-4642
VL - 65
SP - 317
EP - 330
JO - Czechoslovak Mathematical Journal
JF - Czechoslovak Mathematical Journal
IS - 2
ER -