- complete partial order (CPO): "a set with an abstract notion of
the amount of 'information' in each element." [1]

*see Definitions 1-4 in chapter 3 of [1]* - monotonic function: "applying a monotonic function to an element
of CPO always increases the amount of information, unless it is
a fixed point, in which case the element is unchanged." [1]

*see Definition 6 in chapter 3 of [1]* - fixed point: given the vector x in which each element of x
belongs to a CPO, then x is a fixed point for a function f
if f(x) = x.

*see Definition 8 in chapter 3 of [1]*

The Synchronous/Reactive model of computation requires that the blocks (actors) be monotonic functions. Pages 50-52 of [1] show that the Synchronous/Reactive model is deterministic because an SR graph always has a least fixed point.

Note that in Stephen's thesis, he uses the symbol

| | | | --

- Stephen Anthony Edwards,
*The Specification and Execution of Synchronous Reactive Systems*, Ph.D. Thesis, University of California, Berkeley, 1997, Available as UCB/ERL M97/31.

Updated 04/22/02.