Technical Note—A New Proof of the Optimality of the Shortest Remaining Processing Time Discipline

We present a new proof of the fact that for a work-conserving queue, the queuing discipline that always serves a job with the shortest remaining processing time minimizes the number of jobs in the system. A key feature of the proof is a definition of work dominance, allowing comparison of two systems based on the remaining service times of jobs present. Work dominance is both necessary and sufficient for stochastic comparison of the number of jobs present under identical but arbitrary arrival processes.