This Challenge covers the same problems as the First DIMACS Implementation Challenge: Maximum Flows, Minimum-Cost Flows, Multicommodity Flows, Bipartite Matching, Assignment Problem, Matching, and Weighted Matching. We originally planned to have the results presented in Summer 1999 at WAE99, but delays in starting the project mean that we regretfully have to postpone this presentation to ALENEX00 in January 2000. We apologize for the delay; WAE99 organizers have assured us that papers based on the CATS network flow site remain more than welcome.

The goals of the Challenge are

To evaluate progress made since the First DIMACS Challenge.

To stimulate research in the area.

To test CATS (Combinatorial Algorithms Test Sets) core instances.

The participants are urged to use the CATS infrastructure available at the time of the Challenge work, to submit additional data sets to the CATS project, and to provide feedback to the CATS project. The Challenge is expected to test and enhance the infrastructure, in particular the core instances.

The Challenge participants should submit papers to ALENEX00, which will take place January 7-8 in San Francisco, colocated with and immediately preceding SODA 00. The Challenge organizers plan to have a session summarizing results of the Challenge and a session devoted to the status of and the experiences with the CATS project. These sessions will include general discussions as well as presentations by Challenge participants and CATS contributors. The Challenge will continue to the submission deadline for WAE 00 (not yet announced, but to be held in September 2000 in Saarbrücken, Germany).

The first pages supporting Challenge 1.2 have been set up by Andrew Goldberg and can be found through the main CATS pages or directly here.