  We consider a variation of the well-known traveling salesman problem in which
there are multiple agents who all have to tour the whole set of nodes of the
same graph, while obeying node- and edge-capacity constraints require that
agents must not "crash". We consider the simplest model in which the input is
an undirected graph with all capacities equal to one. A solution to the
synchronized traveling salesman problem is called an "agency". Our model puts
the synchronized traveling salesman problem in a similar relation with the
traveling salesman problem as the so-called evacuation problem, or the
well-known dynamic flow (flow-over-time) problem is in relation with the
minimum cost flow problem.
  We measure the strength of an agency in terms of number of agents which
should be as large as possible, and the time horizon which should be as small
as possible. Beside some elementary discussion of the notions introduced, we
establish several upper and lower bounds for the strength of an agency under
the assumption that the input graph is a tree, or a 3-connected 3-regular
graph.
