[sc34wg3] The reflexiveness of isa

Patrick Durusau patrick at durusau.net
Mon Mar 30 09:51:14 EDT 2009


Well, there is a formatting issue (the notes are not numbered 
consecutively through the document) but Note 3 under Section 5 says:

> Other definitions of the above relationships are possible with 
> different properties than defined
> by the TMRM. Such definitions would appear in legends and would be 
> distinguished from those defined
> in the TMRM.

with reference to the TMRM definition of isa.

Having said that, at a minimum I think the "default" definition in the 
TMRM should support other parts of the standard, even though I do think 
we need to leave the door open for other, distinguished definitions of 
that relationship.

Hope you are having a great day!


Lars Marius Garshol wrote:
> According to the current TMRM draft the isa relation is not reflexive.  
> (This issue was identified by Hannes Niederhausen, but I don't see a  
> post from him about it, so I'm writing it up myself.)
> There are two issues with this:
>   - TMDM puts no restrictions on it, so the two are not exactly aligned.
>     Even worse, the TMDM is less restrictive, while if we are going to
>     have differences it's TMRM that should be less restrictive.
>   - TMCL needs to be able to say
>       tmcl:topic-type isa tmcl:topic-type .
>     which means that we have a usecase for a reflexive isa.
> Thoughts on this?
> --Lars M.
> http://www.garshol.priv.no/blog/
> http://www.garshol.priv.no/tmphoto/
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> sc34wg3 mailing list
> sc34wg3 at isotopicmaps.org
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Patrick Durusau
patrick at durusau.net
Chair, V1 - US TAG to JTC 1/SC 34
Convener, JTC 1/SC 34/WG 3 (Topic Maps)
Editor, OpenDocument Format TC (OASIS), Project Editor ISO/IEC 26300
Co-Editor, ISO/IEC 13250-1, 13250-5 (Topic Maps)

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