# Re: definition of derivation?

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Tue, 21 Jun 2011 14:50:59 +0100
Message-ID: <EMEW3|459db3932d3609ffbc83f2f0b47717f1n5KEp708L.Moreau|ecs.soton.ac.uk|4E00A1C3.4010902@ecs.soton.ac.uk>

On 06/21/2011 01:31 PM, Simon Miles wrote:
> Paul, Luc,
>
> I'm OK with the definition, but I think it could be simplified and
> clarified a little, and suggest:
>
> Derivation represents how stuff is transformed from or affected by
> other stuff. A thing B is derived from a thing A if the values of some
> invariant properties of B are at least partially determined by the
> values of some invariant properties of A.
>
> The reasons for this proposed revision:
>
> 1. "A was used (and therefore created) before B was created" means the
> definition of "derivation" is based on those for "use" and
> "generation". This property seems, in practice, necessitated by B
> having been determined by A anyway.
>
I think it's useful if all temporal properties are made explicit somewhere.
It may be in the definition or in an explanation of it.  They are precise,
and they represent a necessary condition for derivation (and other
relations).

My experience is that derivation is dependent on use/generation, but
it may be too early to go to this level of detail.

> 2. The first sentence mixes plural with singular, so it is unclear how
> many things a derivation relates.
>

OK
> 3. The "in the real world" caveat seems unnecessary if "things" are
> defined to be explicitly about the real world. Moreover, if we decide
> to revise the definition of "thing" to cover more than the real world,
> then derivation would also have to be revised.
>
>

Agreed. Once we converge towards common definitions,  we can
have a general preamble about the real world, and avoid this kind
of repetition.

You should definitely add it to the wiki.
Luc
> Thanks,
> Simon
>
> On 20 June 2011 21:07, Paul Groth<pgroth@gmail.com>  wrote:
>
>> Hi All,
>>
>> What do people think of Luc's definition of derivation:
>>
>> - http://www.w3.org/2011/prov
>> /wiki/ConceptDerivation#Definition_by_Luc_.28in_terms_of_properties.29
>> Things represent stuff in the real-world.
>>
>> Definition of Derivation. A derivation represents how stuffs are
>> transformed or affect each other in the real world.
>>
>> A thing B is derived from a thing A if:
>>
>> A was used (and therefore created) before B was created
>> The values of some invariant properties of B are partially determined by
>> the values of some invariant properties of A
>>
>> James you seemed to suggest another way to define derivation or not
>> define it all? Can you be more specific?
>>
>>
>> Thanks,
>> Paul
>>
>>
>> ______________________________________________________________________
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>>
>
>
>

--
Professor Luc Moreau
Electronics and Computer Science   tel:   +44 23 8059 4487
University of Southampton          fax:   +44 23 8059 2865
Southampton SO17 1BJ               email: l.moreau@ecs.soton.ac.uk
United Kingdom                     http://www.ecs.soton.ac.uk/~lavm
Received on Tuesday, 21 June 2011 13:51:35 GMT

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