Oops, in my attempt to show what was happening with a disconnected variable, I messed up completely. My apologies. A corrected version will be available shortly.
peter On 06/27/2016 08:28 AM, james anderson wrote: > >> On 2016-06-27, at 16:05, Peter F. Patel-Schneider <pfpschnei...@gmail.com >> <mailto:pfpschnei...@gmail.com>> wrote: >> >> […] >> >> Project( >> { (x,:b) | >> eval( D(G), >> substitute( >> Join( >> Extend( Z, y, :c ) , >> ToMultiset( Project( ToList( BGP(?z :d ?x) ) , z ) ) >> ) >> (x,:b) ) >> ) /= { } } , >> x >> ) >> >> Project( >> { (x,:b) | >> eval( D(G), >> Join( >> Extend( Z, y, :c ) , >> ToMultiset( Project( ToList( BGP(?z :d :b) ) , z ) ) >> ) >> ) /= { } } , >> x >> ) > > if i follow this, this reduction obtains iff the project has no effect on the > scope the binding for ?x which was established by the outer extend. > is that intended? > > best regards, from berlin, > > > --- > james anderson | ja...@dydra.com <mailto:ja...@dydra.com> | http://dydra.com > > > > >
