The symmetric Generalized Traveling Salesman Problem (GTSP) is a varia
nt of the classical symmetric Traveling Salesman Problem, in which the
nodes are partitioned into clusters and the salesman has to visit at
least one node for each cluster. A different version of the problem, c
alled E-GTSP, arises when exactly one node for each cluster has to be
visited. Both GTSP and E-GTSP are NP-hard problems and find practical
application's in routing, scheduling, and location-routing. In this pa
per, we model GTSP and E-GTSP as integer linear programs and study the
facial structure of the corresponding polytopes. In a companion paper
, the results described in this work have been used to design a branch
-and-cut algorithm for the exact solution of instances up to 442 nodes
. (C) 1995 John Wiley and Sons, Inc.