Hedges: Cleaned up parameter entities

Basically a sequence The hedgeRules that form the backbone of RELAX are pretty simple things - ordered (or potentially unordered) sets of structures.
with properties hedgeRules have names, and can have other metadata attached to them, but the main point is that they are atomic. hedgeRules and their properties are cleared defined pieces which can be interchanged easily.
Only surface when necessary RELAX provides a lot of syntactic sugar to avoid requiring developers to build explicit hedge models every time they want to define elements. Despite that sugar, they underlie every RELAX declaration.
Combinable, subtractable Because hedges are complete sets of structures - not the partial possibilities of parameter entities - and because they have a more mathematical basis than W3C XML Schema types, you can compare different models easily. For translation and version, this can be a substantial advantage.