- From: Dan Connolly <connolly@w3.org>
- Date: Tue, 22 Dec 2009 07:37:18 -0600
- To: jos.deroo@agfa.com
- Cc: public-cwm-talk <public-cwm-talk@w3.org>
On Mon, 2009-12-21 at 21:43 +0100, jos.deroo@agfa.com wrote: > Dan Connolly wrote: > [...] > > It's not sound to go from > > Exists x. P(x) -> Q(x) > > P(a) > > to > > Q(a) > > That is indeed unsound but there is no such rule > with an Exists x where x occurs in the conclusion. It's unsound even if x doesn't occur in the conclusion. Consider an example: is it sound to go from: There is one professor who, if he likes your work, you can get into the school. Professor Bob likes your work. to You can get into the school. ? -- Dan Connolly, W3C http://www.w3.org/People/Connolly/ gpg D3C2 887B 0F92 6005 C541 0875 0F91 96DE 6E52 C29E
Received on Tuesday, 22 December 2009 13:37:21 UTC