Predicate paths versus variables

[Benson Margulies]

Working, I had the following, which does a tiny bit of inference
without turning on the inference engine.

 { ?entity ?pred ?s .
           ?pred rdfs:subPropertyOf rex:relationship . }

Then I tried to get clever and make paths out of these, and I get
rejected. Is there some variation on this that works?

 { ?entity (?pred | (?pred/owl:sameAs) | (owl:sameAs/?pred)) ?s .
           ?pred rdfs:subPropertyOf rex:relationship . }