摘要
The list extremal number f（G） is defined for a graph G as the smallest integer k such that the join of G with a stable set of size k is not ｜V（G）｜-choosable. In this paper, we find the exact value of f（G）, where G is the union of edge-disjoint cycles of length three, four, five and six. Our results confirm two conjectures posed by S. Gravier, F. Maffray and B. Mohar.
The list extremal number f（G） is defined for a graph G as the smallest integer k such that the join of G with a stable set of size k is not ｜V（G）｜-choosable. In this paper, we find the exact value of f（G）, where G is the union of edge-disjoint cycles of length three, four, five and six. Our results confirm two conjectures posed by S. Gravier, F. Maffray and B. Mohar.
基金
The BNSF(I012003)
NSFC(10201022,10571124)
SRCPBMCE(KM 200610028002).
