Re: Issues with evaluating optional: Commutativity of AND

Just to be crystal clear since it's evidently an issue easy to get  
confused on, do you think that for two arbitrary graph patterns G1  
and G2, should

	Join(G1, G2) = Join(G2, G1).

Where Join/2 is inner/natural/standard join.

If so, should the basic connective of graph patterns in SPARQL be Join?

My answers are Yes and Yes. This is the answer in SCS. From what I  
can glean, Andy is in favor a different basic connective (where the  
above relation isn't always true). (I presume he'd agree that Join  
obeys the above equality).

Cheers,
Bijan.