Title - 
	Policy assertion equivalence and generality

Description - 
	Policy assertions are domain specific and opaque from the point of view of the operators. However, there are certain relations between assertions that could be asserted without breaking that opacity. For example, a policy writer could know that, from their point of view, two assertions were exactly the same, or that one was a more general version of the other. For example, one might want to specify that some form of reliable messaging is required, without specifying which specific forms.

Justification -  
	Equivalence pretty much falls out of subsumption/generality. Let me focus on generality.

	Having assertions related by subsumption allows one to write  *general* policies that can be refined in particular cases. It also allows one to *organize* policies in a hierarchy. Thus, even if the only policies one deploys are fully specific, it can be useful to group policies by their semantics.
	
Target - 
	framework

Proposal - 
	One would need two new operators, and a place to put them. Perhaps a header element, which could be external to the policy (thus shared by many). <http://www.mindswap.org/2005/services-policies/> shows how to use policy subsumption.