  We describe mts, which is a generic framework for parallelizing certain types
of tree search programs, that (a) provides a single common wrapper containing
all of the parallelization, and (b) minimizes the changes needed to the
existing single processor legacy code. The mts code was derived from ideas used
to develop mplrs, a parallelization of the reverse search vertex enumeration
code lrs. The tree search properties required for the use of mts are satisfied
by any reverse search algorithm as well as other tree search methods such as
backtracking and branch and bound. mts is programmed in C, uses the MPI
parallel environment, and can be run on a network of computers.
  As examples we parallelize two simple existing reverse search codes:
generating topological orderings and generating spanning trees of a graph. We
give computational results comparing the parallel codes with state of the art
sequential codes for the same problems.
