Order Theory/Series-parallel order
Definition (parallel order):
Let be a family of ordered sets, and define . Then the parallel order on is defined to be the order
- .
Definition (parallel composition):
Let be a family of ordered sets, and define . Then the pair , where is the parallel order on , is called the parallel composition of the sets .
Definition (series order):
Let be a preordered set, and let be a family of ordered sets over . The series order on induced by is the order on given by
- .
Definition (series composition):
Let be a preordered set, and let be a family of ordered sets, and define . Then the pair , where is the series order on , is called the series composition of the sets over .
Definition (series-parallel order):
A series-parallel order is the order of an ordered set that arises from a family of singleton ordered sets (the order being the order that turns into a poset) by applying parallel composition and series composition over a finite number of times.