X-Received: by 10.224.215.194 with SMTP id hf2mr27746483qab.0.1367738303096; Sun, 05 May 2013 00:18:23 -0700 (PDT) X-Received: by 10.50.29.38 with SMTP id g6mr129942igh.11.1367738303043; Sun, 05 May 2013 00:18:23 -0700 (PDT) Path: news.cambrium.nl!textnews.cambrium.nl!feeder1.cambriumusenet.nl!feed.tweaknews.nl!209.85.216.87.MISMATCH!l3no2231608qak.0!news-out.google.com!y6ni0qax.0!nntp.google.com!m7no2258491qam.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.databases.theory Date: Sun, 5 May 2013 00:18:22 -0700 (PDT) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=205.250.214.154; posting-account=FUDi7AoAAACOn42BTSjw9ZlWNiwGl2Nx NNTP-Posting-Host: 205.250.214.154 References: <992824d5-5a8a-4a63-906b-7d3eff2a0b47@googlegroups.com> <51445299$0$582$e4fe514c@dreader34.news.xs4all.nl> <3bd262e6-f9b2-4861-8327-fe31af438cd3@googlegroups.com> <51803a2d$0$6337$e4fe514c@dreader35.news.xs4all.nl> <279c7cc9-3e6f-490f-a692-af98fc134fc3@googlegroups.com> <36bb212d-47ae-4cb0-bf2b-a926ff2173d4@googlegroups.com> <54934075-6dd1-4f96-9c6f-50db406a7586@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: Subject: Re: How to normalize this? From: compdb@hotmail.com Injection-Date: Sun, 05 May 2013 07:18:23 +0000 Content-Type: text/plain; charset=ISO-8859-1 Xref: news.cambrium.nl On Saturday, May 4, 2013 4:28:01 PM UTC-7, com...@hotmail.com wrote: > Eg if your only predicate/variable on attributes A1,..,An is p(A1,...,An) then the only predicates you can express on a subset of Ai,... involve "exists Ai,... p(A1,...,An)". Oops, that's "exists ...all but Ai,... p(A1,...,An)". philip