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Klyne Contexts: 5.3-5.5 resources, languages and frames

From: Jonas Liljegren <jonas@rit.se>
Date: 23 Nov 2000 13:06:41 +0100
To: Graham Klyne <GK@Dial.pipex.com>
Cc: Wraf development <rdf@uxn.nu>, RDF interest group <www-rdf-interest@w3.org>
Message-ID: <87n1eqlwoe.fsf@astral.paranormal.se>
I don't understand why we must have contexts in place of resources.
Why doesn't normal resources work?  (I hadn't read the MEMO the last
time this was discussed.)


One example says, in part:

      [MyCar] --isa--> [FordEscort]
      [     ] --rdfc:asserts-->
        {
        [TheBody] ----color-----> "red"
        [TheEngine] --capacity--> "1600cc"
        }


The normal way to do this would be:

 S1: [my:Car] --type--> [FordEscort]
 S2: [my:Car] --body--> [my:Body]
 S3: [my:Body] --color--> [red]
 S4: [my:Car] --engine--> [my:Engine]
 S5: [my:Engine] --capacity--> [my:Capacity]
 S6: [my:Capacity] --unit--> [cc]
 S7: [my:Capacity] --value--> "1600"


No need for special constructions.  Plain RDF works fine.  The "my"
things above are placed in a local namespace.


Your example above makes a context out of MyCar.  I don't think that
is a meaningful context.  It's not the car who asserts it's
properties.

I will discuss the basic use of contexts later (in its relation to
models).  But let us use it for this example:

 S8: [my:Klyne] --asserts--> [S1]
 S9: [my:Klyne] --asserts--> [S2]
 S10: [my:Klyne] --asserts--> [S3]
 S11: [my:Klyne] --asserts--> [S4]
 S12: [my:Klyne] --asserts--> [S5]
 S13: [my:Klyne] --asserts--> [S6]
 S14: [my:Klyne] --asserts--> [S7]


The example continues:


      [FordEscort] --asserts-->
        {
        [TheBody] ----material---> "steel"
         :
        [TheEngine] --cylinders--> "4"
        [         ] --valves-----> "8"
         :
        (etc.)
        }


The inference rules (my interpretation of rdfc:assumes and
rdfc:asserts) could then be used to find the other properties of the
car.

 S15: [my:Klyne] --asserts--> [GeneralCarContext]
 S16: [GeneralCarContext] --asserts--> [GCC1]
 S17: [GCC1] --assumes--> [S18]
 S18: [var:1] --type--> [FordEscort]
 S19: [GCC1] --asserts--> [S20]
 S20: [var:1] --body--> [var:2]
 S21: [var:2] --material--> [steel]
 S22: [GCC1] --asserts--> [S23]
 S23: [var:1] --engine--> [var:3]
 S24: [var:3] --cylinders--> "4"
 S25: [var:3] --valves--> "8"


This is how I would do "forward" inferencing.



Maby should continue this discussion in rdf-logic?
  Haven't compared this to DAML yet...

-- 
/ Jonas Liljegren

The Wraf project http://www.uxn.nu/wraf/
Sponsored by http://www.rit.se/
Received on Thursday, 23 November 2000 07:05:31 GMT

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