Chapter 14. The Facet Algebra
The facet algebra is a collection of operations for composing facets from one or more domains. The facet product and sum operations define classical conjunctive and disjunctive composition operations. Taking the product of two facets defines a new facet that satisfies both of the original specifications. Similarly, taking the sum of two facets defines a new facet that satisfies either of the original specifications. Using facet product and sum provides direct language support for concurrent engineering where multiple specifications must be simultaneously valid.
let forms define the mechanisms for selecting between models and defining local models respectively. Facet-typed applications of