On -pairable graphs from trees
The concept of the -pairable graphs was introduced by Zhibo Chen (On -pairable graphs, Discrete Mathematics 287 (2004), 11–15) as an extension of hypercubes and graphs with an antipodal isomorphism. In the same paper, Chen also introduced a new graph parameter , called the pair length of a graph , as the maximum such that is -pairable and if is not -pairable for any positive integer . In this paper, we answer the two open questions raised by Chen in the case that the graphs involved...