 
Summary: AN ANT COLONY SYSTEM APPROACH FOR SOLVING THE ATLEAST VERSION OF THE
GENERALIZED MINIMUM SPANNING TREE PROBLEM
Arindam K. Das
University of Washington
arindam@ee.washington.edu
Payman Arabshahi, Andrew Gray
Jet Propulsion Laboratory
{payman,gray}@jpl.nasa.gov
ABSTRACT
We consider the "at least" version of the Generalized Min
imum Spanning tree problem (LGMST). Unlike the MST,
the LGMST is known to be NPhard. In this paper, we pro
pose an ant colony system based solution approach for the
LGMST. A key feature of our algorithm is its use of ants of
different behavioral characteristics, which are adapted over
time. Computational results on datasets used in earlier lit
erature indicate that our algorithm provides similar or better
results for most of them.
1. INTRODUCTION
Given an undirected graph G = (N, E), where N is the set
