Re: [ontolog-forum] Fwd: Ontolog invited speaker session - Dr. Mark Greaves on the Halo Project - Thu 2008.06.19

At 8:37 PM -0400 6/25/08, Adrian Walker wrote:
>Hi John --

Allow me to respond also.

>You wrote...
>
>It's important for us to develop Common Logic as the growth path
>for ontologies and to incorporate CL in the Semantic MediaWiki.
>
>Anything currently represented in either the Semantic Web notations
>or relational databases can be mapped to Common Logic.  And the
>more compact CL notation is vastly more efficient in storage space,
>transmission time, and computation time than the current Semantic
>Web notations.
>
>We should position CL as the foundation for Semantic Web 3.0.
>
>You may like therefore to address Chris Welty's point that CL 
>appears infeasible for the W3C rule interchange project.  In slide 
>11 of [1], Chris says:
>
>The CL and IKL approach [is] deprecated: infeasible for this group 
>[W3C Rule Interchange], as major differences appeared irreconcilable 
>(e.g. non-mon vs. mon)

He is there referring to a particular approach, viz. to adopt a 
highly expressive language into which all rule languages can be 
translated, which was used in the IKRIS project which produced IKL. 
If however you read on in the same slides, you will find that the 
language finally adopted as the initial Rule standard, though much 
weaker than CL, in fact is a classical logic with a classical 
negation, just like negation in every other logic with a clear 
semantics.

>The fundamental difficulty seems to be

That isnt the fundamental difficulty for RIF.

>that CL and IKL have chosen a theoretical semantics for negation

Its not especially 'theoretical'. It is simply what negation means in 
ordinary language. If you say cows are white, and I say, No, cows are 
brown; then my "no" says that what you said is false. That simply is 
what negation means. This is a common-sense, pre-theoretical notion 
of negation. So-called 'negation as failure' is the theoretical 
notion, and it only arises from database theory. The basic snag with 
negation as failure is that it is almost always not valid. It is 
simply wrong. The cases where you can validly infer, from a failure 
to prove P, that P is false, are extremely rare. They only occur in 
specialized circumstances in specialized tasks performed by 
specialists in certain limited cases. Can you prove that every finite 
abelian group can be expressed as the direct sum of cyclic subgroups 
of prime-power order? Answer quickly. Suppose, just for the sake of 
argument, that you can't. Are you justified in concluding that this 
is false? Maybe you had better hedge your bets.

>from before the computer era, whereas SQL and most logic based 
>programming languages use a different meaning for negation -- one 
>that can also be formalized, e.g. as in [2].

It can be formalized, for sure. It can in fact be formalized in many 
different, incompatible, ways. All of them however make it vividly 
clear that this is not a generally correct inference rule.

Pat

>
>Thanks for your thought about this.
>
>                                        -- Adrian
>
>[1] 
><http://ontolog.cim3.net/file/resource/presentation/ChrisWelty_20080612/W3C-Rules-Interchange-Format--ChrisWelty_20080612.ppt>http://ontolog.cim3.net/file/resource/presentation/ChrisWelty_20080612/W3C-Rules-Interchange-Format--ChrisWelty_20080612.ppt
>
>[2]  Backchain Iteration: Towards a Practical Inference Method that is Simple
>   Enough to be Proved Terminating, Sound and Complete. Journal of 
>Automated Reasoning, 11:1-22
>
>Internet Business Logic
>A Wiki and SOA Endpoint for Executable Open Vocabulary English over 
>SQL and RDF
>Online at <http://www.reengineeringllc.com>www.reengineeringllc.com 
>Shared use is free
>
>Adrian Walker
>Reengineering
>
>
>
>
>
>On Mon, Jun 23, 2008 at 10:54 PM, John F. Sowa 
><<mailto:sowa@bestweb.net>sowa@bestweb.net> wrote:
>
>Peter,
>
>Thanks for posting the audio for Mark Greaves talk.  I wasn't
>able to log in for the talk, but I read the slides.  The audio
>covers some important points that are not in the slides:
>
>
><http://ontolog.cim3.net/cgi-bin/wiki.pl?ConferenceCall_2008_06_19>http://ontolog.cim3.net/cgi-bin/wiki.pl?ConferenceCall_2008_06_19
>
>The Semantic MediaWiki is very important work, and since it is
>available as open source, we should use it.
>
>But one important point that Mark mentioned is that the reasoning
>capabilities of current Semantic Web technology is very weak.
>RDF(S), OWL, SPARQL, and RuleML are useful, but weak subsets
>of Common Logic.
>
>It's important for us to develop Common Logic as the growth path
>for ontologies and to incorporate CL in the Semantic MediaWiki.
>
>Anything currently represented in either the Semantic Web notations
>or relational databases can be mapped to Common Logic.  And the
>more compact CL notation is vastly more efficient in storage space,
>transmission time, and computation time than the current Semantic
>Web notations.
>
>We should position CL as the foundation for Semantic Web 3.0.
>
>John
>
>
>
>
>
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