ON THE CIRCUMFERENCES OF 1-TOUGH GRAPHS

摘要

A connected graph G is called t-tough if t · ω (G — S) ≤ | S| for any subset S of V(G) where t is a real number and ω(G—S) is the number of components of G- S. Obviously, a 1-tough graph is 2-connected. The circumference c(G) of graph G is the length of a longest cycle of G. There is an extensive literature