Ternary algebra has been used for detection of hazards in logic circuits since 1948. Process spaces have been introduced in 1995 act models of concurrent processes. Surprisingly, process spaces turned out to be special ternary algebras. We study symmetry in process spaces; this symmetry is analoguous to duality, but holds among three algebras. An important role is played here by the uncertainty partial order, which has been used since 1972 in algebras dealing with ambiguity. We prove that each process space consists of three isomorphic Boolean algebras and elements related to partitions of a set into three blocks.
Janusz A. Brzozowski, Radu Negulescu