Find out in data if resources are connected

[Mikael Pesonen]

Hi,
is there a more efficient way to find out if two entities are connected? 
This

ASK {
      ?s ((<>|!<>)|^(<>|!<>))* ?o
  }


works for short, couple of relations long, paths but becomes too slow 
quickly. Maybe something like the list:member method for RDF lists?

BR
Mikael