- From: David McNeil <dmcneil@revelytix.com>
- Date: Mon, 28 Nov 2011 08:34:08 -0600
- To: "Eric Prud'hommeaux" <eric@w3.org>
- Cc: public-rdf-dawg-comments@w3.org
Received on Monday, 28 November 2011 14:34:43 UTC
On Thu, Nov 24, 2011 at 2:32 PM, Eric Prud'hommeaux <eric@w3.org> wrote: > LeftJoin(Ω1, Ω2, expr) = > { merge(μ1, μ2) | μ1 in Ω1 and μ2 in Ω2, and μ1 and μ2 are compatible > and expr(merge(μ1, μ2)) is true } > ∪ > { μ1 | μ1 in Ω1 | ∄ μ2 in Ω2 | μ1 and μ2 are compatible and > expr(merge(μ1, μ2)) is true } > > ? > Eric - Doesn't this definition have a problem in the case where there is a u1 for which there is a u2 that is compatible and expr(...) is true and there is another u2 that is compatible and expr(...) is false? I think the definition you gave in this email would only produce a single output for u1, whereas the main definition of LeftJoin in the SPARQL 1.1 draft would have two outputs for u1: one to reflect the u2 where expr(...) is true and another to reflect the u2 where expr(...) is false. -David
Received on Monday, 28 November 2011 14:34:43 UTC