Partial Order Reduction (POR) is a technique used in computer science to reduce the size of the state-space that needs to be searched by a model checking or automated planning and scheduling algorithm. This reduction is achieved by exploiting the commutativity of concurrently executed transitions that result in the same state.

• model checking
• automated planning and scheduling
• concurrency and parallelism

For instance, consider a system with two processes that can communicate through a shared buffer. If the processes are commutative, meaning that the order in which they access the buffer does not affect the outcome, then POR can be applied to reduce the state-space of the system. The algorithm starts by considering all possible transitions of both processes, and then reduces the state-space by eliminating redundant transitions that result in the same state.

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