Summary: On system executions and states
Department of mathematics and computer science
Ben-Gurion University, Be'er Sheva, ISRAEL.
March 12, 1995
An approach for modeling dynamic situations where several pro-
cesses execute concurrently is described here. We address basic issues
such as what is an `event'? What is a `state' of a system? How
should time be represented? etc. In this, we use the concepts `system
execution' and `pomset' dened by Lamport and Gischer.
The notion of a system execution is extended in such a way that
a state is just a peculiar system execution, one in which no event
precedes another|it is the description of a moment. This allows to
demonstrate within a single framework the duality between two ap-
proaches to modeling concurrency: the one based on events and the
other on states.
The notions of a structure and a model were proved to be very useful in
mathematics, but it is not obvious how to adapt them to represent an ever