Mike Linksvayer | 10 Jun 18:37 2009

See you in Torino!

Many of you I hope!

Please share http://creativecommons.org/weblog/entry/15095 encouraging
people to attend the CC Tech Summit and COMMUNIA conference later this
month. Registration deadlines approaching.

Thanks,
Mike

p.s. Click on "CC BY-SA" in the photo caption on
http://creativecommons.org/weblog/entry/15095 to see ccREL in action
on the license deed -- attribution info and copy&paste HTML is
auto-populated from the photo's license metadata.
Christoph LANGE | 19 Jun 13:08 2009
Picon

How to negate cc:permits, cc:prohibits, cc:requires?

Dear all,

  we are working on re-specifying the integration of the ccREL ontology into
the mathematical markup language OMDoc (http://www.omdoc.org) in a more formal
way.  Now I wonder: Is there any way of saying that some Permission does _not_
hold (e.g. that distribution is not permitted, or should I rather say
"prohibited"?), or that some Prohibition does not hold (e.g. that
commercial use is not prohibited, or should I rather say "permitted"?) ?

XY cc:permits cc:CommercialUse

is not really intended by the current implementation of the ccREL ontology.
So do you rather assume negation as failure?  I.e. that if "XY cc:prohibits
cc:CommercialUse" is _not_ explicitly mentioned, then we assume that
commercial use is not prohibited?  But, if so, wouldn't that conflict with the
open world nature of RDFS?

Thanks in advance for any hints,

Christoph

--

-- 
Christoph Lange, Jacobs Univ. Bremen, http://kwarc.info/clange, Skype duke4701

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(Continue reading)

Nathan Yergler | 19 Jun 19:14 2009

Re: How to negate cc:permits, cc:prohibits, cc:requires?

Hi Christoph,

In all the CC licenses, if Commercial Use is not explicitly
prohibited, it is considered allowed.  We've previously looked at
expressing this sort of additional information with OWL but haven't
released anything.

If there are revisions we should consider, I'd be open to proposals.

Nathan

On Fri, Jun 19, 2009 at 4:08 AM, Christoph
LANGE<ch.lange@...> wrote:
> Dear all,
>
>  we are working on re-specifying the integration of the ccREL ontology into
> the mathematical markup language OMDoc (http://www.omdoc.org) in a more formal
> way.  Now I wonder: Is there any way of saying that some Permission does _not_
> hold (e.g. that distribution is not permitted, or should I rather say
> "prohibited"?), or that some Prohibition does not hold (e.g. that
> commercial use is not prohibited, or should I rather say "permitted"?) ?
>
> XY cc:permits cc:CommercialUse
>
> is not really intended by the current implementation of the ccREL ontology.
> So do you rather assume negation as failure?  I.e. that if "XY cc:prohibits
> cc:CommercialUse" is _not_ explicitly mentioned, then we assume that
> commercial use is not prohibited?  But, if so, wouldn't that conflict with the
> open world nature of RDFS?
>
(Continue reading)

Christoph Lange | 19 Jun 22:37 2009
Picon

Re: How to negate cc:permits, cc:prohibits, cc:requires?

Hi Nathan,

On Fri, Jun 19, 2009 at 7:14 PM, Nathan
Yergler<nathan <at> creativecommons.org> wrote:
> If there are revisions we should consider, I'd be open to proposals.

thanks for your explanations. As far as my own work with ccREL is
concerned, my concerns were mostly theoretical, as I expect most of
our mathematical documents to use the standard CC licenses.

> In all the CC licenses, if Commercial Use is not explicitly
> prohibited, it is considered allowed.  We've previously looked at
> expressing this sort of additional information with OWL but haven't
> released anything.

However, I think that this kind of negation as failure is not
consistent with the open world assumption made by OWL and RDFS. If
Alice defines a custom license L in one of her documents and wants to
say that commercial use is allowed, her only choice is to say nothing,
i.e. to leave the RDF triple "L cc:prohibits cc:CommercialUse" out.
But what if Bob somewhere else on the web says "L cc:prohibits
cc:CommercialUse", and then some crawler crawls both Alice's and Bob's
definitions?

For that reason, I think it would be better to explicitly be able to
state negative facts.  Depending on how this is implemented in OWL,
one would be able to say in the ccREL ontology that e.g. "prohibits X"
and "permits X" contradict each other.  Then, in the scenario outlined
above, it could still happen that Alice's and Bob's contradicting
facts are merged together, but then any reasonable semantic web
(Continue reading)

Patrick Peiffer | 20 Jun 00:39 2009
Picon

Re: How to negate cc:permits, cc:prohibits, cc:requires?

Hi,

I'm definitely not a semantic web specialist but these "Open World vs. Closed World issues" were raised in the W3C team comment on ccREL, http://www.w3.org/Submission/2008/02/Comment

Is this a liability for integrating ccREL into an RDFS / OWL sematic environement?

If yes, what does it take to change that? Nathan, how far did you go with OWL and what stopped you?

Best, Patrick Peiffer
cc-Luxembourg



On Fri, Jun 19, 2009 at 10:37 PM, Christoph Lange <ch.lange-shsDHVVYhWkzrYMiTdX2twxv4HzkJkzx@public.gmane.org> wrote:
Hi Nathan,

On Fri, Jun 19, 2009 at 7:14 PM, Nathan
Yergler<nathan <at> creativecommons.org> wrote:
> If there are revisions we should consider, I'd be open to proposals.

thanks for your explanations. As far as my own work with ccREL is
concerned, my concerns were mostly theoretical, as I expect most of
our mathematical documents to use the standard CC licenses.

> In all the CC licenses, if Commercial Use is not explicitly
> prohibited, it is considered allowed.  We've previously looked at
> expressing this sort of additional information with OWL but haven't
> released anything.

However, I think that this kind of negation as failure is not
consistent with the open world assumption made by OWL and RDFS. If
Alice defines a custom license L in one of her documents and wants to
say that commercial use is allowed, her only choice is to say nothing,
i.e. to leave the RDF triple "L cc:prohibits cc:CommercialUse" out.
But what if Bob somewhere else on the web says "L cc:prohibits
cc:CommercialUse", and then some crawler crawls both Alice's and Bob's
definitions?

For that reason, I think it would be better to explicitly be able to
state negative facts.  Depending on how this is implemented in OWL,
one would be able to say in the ccREL ontology that e.g. "prohibits X"
and "permits X" contradict each other.  Then, in the scenario outlined
above, it could still happen that Alice's and Bob's contradicting
facts are merged together, but then any reasonable semantic web
software would _report_ this contradiction.

Not sure if you agree with that reasoning, and, if so, what you'd like
to do.  There is not so much traffic on this list, are there any
semantic web experts around?

Cheers,

Christoph

--
Christoph Lange, http://de.wikipedia.org/wiki/Benutzer:Langec, ICQ# 51191833

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