Re: Question on the SPARQL spec

From: Lee Feigenbaum <lee@thefigtrees.net>
Date: Sun, 28 Oct 2007 15:05:12 -0400
Message-ID: <4724DD68.1080808@thefigtrees.net>
To: Francis McCabe <frankmccabe@mac.com>

```
Yes. This is correct in the editor's draft.

http://www.w3.org/2001/sw/DataAccess/rq23/rq25.html

Lee

Francis McCabe wrote:
>
> The semantics of LeftJoin read
>
> Definition: LeftJoin
> Let Ω1 and Ω2 be multisets of solution mappings and F a filter. We define:
>
> LeftJoin(Ω1, Ω2, expr) = Filter(expr, Join(Ω1, Ω2)) set-union Diff(Ω1,
> Ω2, expr)
>
> card[LeftJoin(Ω1, Ω2, expr)](μ) = card[Filter(expr, Join(Ω1, Ω2))](μ) +
> card[Diff(Ω1, Ω2, expr)](μ)
>
>
>
>
> Definition: LeftJoin
>
> Let Ω1 and Ω2 be multisets of solution mappings and expr a filter. We
> define:
>
> LeftJoin(Ω1, Ω2, expr) = Filter(expr, Join(Ω1, Ω2)) set-union Diff(Ω1,
> Ω2, expr)
>
> card[LeftJoin(Ω1, Ω2, expr)](μ) = card[Filter(expr, Join(Ω1, Ω2))](μ) +
> card[Diff(Ω1, Ω2, expr)](μ)
>
>
>
>
> Frank McCabe
>
>
>
```
Received on Sunday, 28 October 2007 19:05:27 UTC

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