Welcome to the KCTLIB, the first library for the Edge-Weighted K-Cardinality Tree (KCT) problem. This site was initiated in January 2003 following a paper on three new metaheuristic approaches to tackle the KCT problem (download), which is published in Computers & Operations Research. The primary aims of the site are the distribution of benchmark instances, the distribution of software such as programs to tackle the KCT problem, and the collection of best known solutions to benchmark instances. Furthermore, it aims to be a valuable source of information on the KCT problem in general. In the creation of the site we oriented ourselves at "famous" examples such as the TSPLIB and the QAPLIB.