- From: Dan Connolly <connolly@w3.org>
- Date: Tue, 23 Feb 2010 16:16:15 -0600
- To: public-cwm-talk@w3.org
I'm re-implementing N3Logic in scala... in particular, parsing N3 syntax into Coherent formulas. I'm trying to figure out how existential variables work in N3, and I'm surprised about something. Consider: There's somebody that Bob likes and Fred likes. And everybody that Alice likes also likes this somebody. Also, Alice likes Trina. Does Trina like this somebody? Of course Trina does, but when I try to write the problem down in N3, cwm doesn't handle it as I'd expect. cwm concludes that Trina likes something, but not that Trina likes the same somebody that Bob and Fred like. $ cat ...varscope1.n3 @prefix : <evarscope1#>. @keywords is, of, a. bob likes _:somebody. fred likes _:somebody. { alice likes ?X } => { ?X likes _:somebody }. alice likes trina. $ cwm.py ...varscope1.n3 --think #Processed by Id: cwm.py,v 1.197 2007/12/13 15:38:39 syosi Exp # using base file:///home/connolly/projects/rdfsem/src/test/resources/varscope1.n3 # Notation3 generation by # notation3.py,v 1.200 2007/12/11 21:18:08 syosi Exp # Base was: file:///home/connolly/projects/rdfsem/src/test/resources/varscope1.n3 @prefix : <evarscope1#> . @prefix va: <#> . @forAll va:X. @forSome va:_g0 . :alice :likes :trina . :bob :likes va:_g0 . :fred :likes va:_g0 . :trina :likes [ ] . { :alice :likes va:X . } <http://www.w3.org/2000/10/swap/log#implies> {va:X :likes [ ] . } . #ENDS The surprise is bad news, but the good news is that cwm's way of reading this formula does fit inside coherent logic, which makes my coding goal straightforward... -- Dan Connolly, W3C http://www.w3.org/People/Connolly/ gpg D3C2 887B 0F92 6005 C541 0875 0F91 96DE 6E52 C29E
Received on Tuesday, 23 February 2010 22:16:18 UTC