Re: Paper on Quantities in OWL - response on a minor point

On Tue, Aug 26, 2008 at 9:08 AM, David Leal
<david.leal@caesarsystems.co.uk> wrote:
> Dear Bijan,
>
> I need to do much more work on your paper (and so will be quiet for a
> while).

Don't feel required to be quiet. The paper is definitely elliptical on
some points and presumes a bit of experience with OWL Datatypes and
Data Ranges.

> However, I would like to respond immediately on a minor point.
>
> You say:
>>Actually, MathML does not have any support for quantities per se, afaict,
> and doesn't plan to:
>>   <http://www.w3.org/TR/mathml-units/>
>
> This is not correct. The document you reference has almost all the
> capabilities that are needed for quantities and units, except that they are
> only accessible within the "MathML world".

My point was that this is a WG note, not a rec track document.
Publishing a note doesn't *mean* that no further work will *ever* be
done, but it is an indicator that a WG isn't planning on doing more
(i.e., Notes are a "terminal" publication state).

Given the incompleteness (even no URIs) it's clear that you can't just
adopt it (the way, for example, we adopt linear equations).

(When I said that MathML was a
> "closed world", I meant this in a general sense meaning that MathML has a
> scope limited to mathematics, rather than in the technical sense related to
> inferencing.)
>
> In MathML, I can state that:
>
> - the quantity x (local name) with URI http://www.example.com/x is a length:
>
>  <semantics>
>  <csymbol definitionURL="http://www.example.com/x">x</csymbol>
>  <annotation definitionURL='http://.../dimension/length'/>
>  </semantics>
>
> - the unit quantity m (local name) with URI http://.../units/metre is a length:
>
>  <semantics>
>  <csymbol definitionURL="http://.../units/metre">m</csymbol>
>  <annotation definitionURL='http://.../dimension/length'/>
>  </semantics>
>
> - x = 10.3 m
>
>  <apply>
>  <eq/>
>  <csymbol definitionURL="http://www.example.com/x">x</csymbol>
>  <apply>
>   <times/>
>   <cn>10.3</cn>
>   <csymbol definitionURL="http://.../units/metre">m</csymbol>
>  </apply>
>  </apply>

Yeah, we may or may not adopt something like this when we go to
equational support. Whether we adopt this, strictly, or some other
variant is open.

> This is fine, except that:
> 1) it is MathML and not RDF/OWL;

Well, in the current equation support proposal:
    <http://www.w3.org/2007/OWL/wiki/Data_Range_Extension:_Linear_Equations>

We've just adopted MathML content syntax, so this extension is
(syntactically) trivial.

However, it won't do for datatypes in the normal sense, that is true,
the way our proposal does.

> 2) it needs an extension for quantities which are described using scales
> rather than units (e.g. Celsius, ITS90, Richter, decibel, Moh, etc.);
> 3) somebody has to provide the namespace "http://www.../" used in the MathML
> document - that somebody should be BIPM or ISO.
[snip]

I think it'd be harmless to have the W3C or even webont.org supply
this. As long as the table is accurate and up to date, I don't
(personally) much care who supplies the namespace.

-- 
Cheers,
Bijan.

http://clarkparsia.com

Received on Tuesday, 26 August 2008 09:42:08 UTC