|
In computer science, specifically in the field of formal verification, well-structured transition systems (WSTSs) are a general class of infinite state systems for which many verification problems are decidable, owing to the existence of a kind of order between the states of the system which is compatible with the transitions of the system. WSTS decidability results can be applied to Petri nets, lossy channel systems, and more. == Formal definition == Recall that a well-quasi-ordering on a set is a quasi-ordering (i.e., a preorder or reflexive, transitive binary relation) such that any infinite sequence of elements , from contains an increasing pair with . The set is said to be well-quasi-ordered, or shortly wqo. For our purposes, a ''transition system'' is a structure , where is any set (its elements are called ''states''), and (its elements are called ''transitions''). In general a transition system may have additional structure like initial states, labels on transitions, accepting states, etc (indicated by the dots), but they do not concern us here. A well-structured transition system consists of a transition system , such that * is a well-quasi-ordering on the set of states. * is upward compatible with : that is, for all transitions (by this we mean ) and for all such that , there exists such that (that is, can be reached from by a sequence of zero or more transitions) and . 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Well-structured transition system」の詳細全文を読む スポンサード リンク
|