We investigate the use of Gomory's mixed integer cuts within a branch-
and-cut framework. It has been argued in the literature that ''a marri
age of classical cutting planes and tree search is out of the question
as far as the solution of large-scale combinatorial optimization prob
lems is concerned'' [16] because the cuts generated at one node of the
search tree need not be valid at other nodes. We show that it is poss
ible, by using a simple lifting procedure, to make Gomory cuts generat
ed at a node of the enumeration tree globally valid in the case of mix
ed 0-1 programs. The procedure essentially amounts to treating the var
iables fixed at 0 or 1 as if they were free. We also show why this lif
ting procedure is not valid for general (other than 0-1) mixed integer
programs. Other issues addressed in the paper are of a computational
nature, such as strategies for generating the cutting planes, deciding
between branching and cutting, etc. The result is a robust mixed inte
ger program solver.