Properties of Edge-Tough Graphs

 In [6] the author defined a new property of graphs namely the edge-toughness. It was proved in [6] that a 2t-tough graph is always t-edge-tough. It is proved in the present paper that this is not true for (2t−ε)-tough graphs if t is a positive integer. A result of Enomoto et al. in [5] implies that every 2-tough graph has a 2-factor. In the present paper it is proved that every 1-edge-tough graph has a 2-factor. This is a sharpening of the previous statement. Received: July 10, 1996 Revised: March 4, 1998