Editorial issues

The rule for "Empty" states

    |<wsp:All />| expresses a policy with zero policy assertions. Note
    that since |wsp:Policy| is equivalent to |wsp:All|, |<wsp:Policy />|
    is therefore equivalent to |<wsp:All />|, i.e., a policy alternative
    with zero assertions.

Elsewhere it says that <All/> represents alternatives, not policies, and
there is certainly a distinction between an empty policy and an empty
alternative.  Should the first sentence read " ... a policy
/alternative/ with zero policy assertions"?

Conversely, it seems odd that <Policy/> should denote an /alternative/
not a policy.  Intuitively, an empty <Policy/> seems like it should
denote either a policy with no alternatives, or perhaps a policy with a
single empty alternative.

------------------------------------------------------------------------

The section on intersection states

    If two alternatives are compatible, their intersection is an
    alternative containing all of the assertions in both alternatives.

This sounds like set union to me (except that we're not necessarily
talking about sets).  If I talk about "all the people in both the USA
and Canada", I'm not talking about people on the border, I'm talking
about the combined populations.  However, this seems counter-intuitive
in the context of intersection, and "all of the assertions in both
alternatives" could be parsed as meaning "all of the assertions which
are both in one alternative and in the other", that is, the set
intersection (except that we're not necessarily talking about sets).

It would be good to clarify exactly what is meant.