The objective of this paper is to develop polynomial algorithms far th
e open shop makespan problem. It is shown that when a machine majorize
s all other machines and the ith largest processing time on that machi
ne is at least as large as the processing times of all operations on m
achines i through m, the problem becomes polynomially solvable. The ut
ilization of the duality property between jobs and machines leads to a
similar polynomial algorithm when a job majorizes all other jobs and
the ith largest processing time of this job is at least as large as th
e processing times of all operations for jobs i through n.