From: <jos.deroo.jd@belgium.agfa.com>

Date: Fri, 19 Oct 2001 02:51:43 +0100

To: timbl@w3.org

Cc: w3c-rdfcore-wg@w3.org

Message-Id: <OF05F51044.E0EDEBA2-ON41256AEA.00060C5E@bayer-ag.com>

Date: Fri, 19 Oct 2001 02:51:43 +0100

To: timbl@w3.org

Cc: w3c-rdfcore-wg@w3.org

Message-Id: <OF05F51044.E0EDEBA2-ON41256AEA.00060C5E@bayer-ag.com>

Tim, > I was going to ask you about whether your were thinking of building > in functions to Euler. Yes, and I was thinking the last couple of weeks to ask you about which ones and this is the nicest work I can imagine! > The functional Properties I am using for this sort of stuff at the moment > are: > > log:semantics - The graph (formula) you get if you get a representatioon > of somthing and parse its semantics ok, seems a must > log:conjunction - The graph you get from merging a list of graphs > log:conclusion - The graph you get from taking all the rules in a graph > and applying them > the graph, putting new statements into the graph. > Closure under forward chain inference. > Same as cwm -think log:conclusion will be a challenge we've done attempts with a query _:s _:p _:o . > log:includes - A binary operator, true if one graph is a subgraph of > the other, modulo a bit of inference and > variable subsitution. > log:directlyIncludes - A binary operator, true if one graph is a > subgraph of the other, modulo only > variable subsitution. we try that along the 'entail' way, and control the kind of inferencing with what Pat calls 'namespace entailment' > I haven't got conjunction and conclusion running yet. > http://www.w3.org/2000/10/swap/test/includes/check.n3 > is an example of using some of these to check that predicates > used in a document are indeed defined in the schema. > > I have not used "entails under RDFS" - I just merge the RDFS axioms and then > use log:conclusion. > > So, I would write a test something like > > { this log:forAll :p, :r, :x, :z. > { :p rdfs:range :r . :x :p :z } log:shouldEntail { :z a :r }. > } a :test. > > Then I would define use of shouldEntail with something *like* (untested!!) > > { :T a :test. > :T log:includes { :F log:shouldEntail :G}. > <rdfsRules.n3> log:semantics :R. > [ log:conjunction ( :F :R) ] log:conclusion [ log:includes :G ]. } > log:implies { :T a :success }. > > plus a few combinations with notIncludes to do negative tests. haven't thought how to support that one... > I expect if one had a backward chainer, one would use a proof search > instead of > the conclusion...includes combination: > > [ log:conjunction ( :F :R) ] euler:supportsProofOf G ]. } log:implies > { :T a :success }. I will start with the log:semantics (and also do () lists) and then log:conjunction This is of real great help, thanks! JosReceived on Thursday, 18 October 2001 20:51:54 EDT

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