RE: definitions for SELECT, projection, substitution [was: [Fwd: Re:...]]

On Wed, 2004-11-10 at 18:23 +0000, Seaborne, Andy wrote:
> > (http://www.w3.org/2001/sw/DataAccess/rq23/#MultipleMatches 1.120 )
> Text added in v1.129

OK, but now there's some redundancy; the definition I gave
for substituion is intended to replace the definitions
of binding and set of bindings.

These define pretty much the same construct:

"A substitution S is a functional relation from variables to RDF terms.
We write S[v] for
the term that S pairs with the variable v."

and

"A binding is a pair which defines a mapping from a variable to an RDF
Term. If B is such a binding, var(B) is the variable of the binding, and
val(B) is the RDF term.

...

A binding, B, defines a substitution subst(T, B) on triple T that
replaces every occurrence of the variable, var(B), with the
corresponding RDF Term, val(B)."


I hope to have a suggestion about how to resolve the redundancy
after I study the definitions for SOURCE (and perhaps optionals).
 
-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E