From: Brian McBride <bwm@hplb.hpl.hp.com>

Date: Tue, 25 Feb 2003 14:37:57 +0000

Message-Id: <5.1.0.14.0.20030225143749.036fa8b8@localhost>

To: pat hayes <phayes@ai.uwf.edu>, herman.ter.horst@philips.com

Cc: www-rdf-comments@w3.org

Date: Tue, 25 Feb 2003 14:37:57 +0000

Message-Id: <5.1.0.14.0.20030225143749.036fa8b8@localhost>

To: pat hayes <phayes@ai.uwf.edu>, herman.ter.horst@philips.com

Cc: www-rdf-comments@w3.org

At 14:33 24/02/2003 -0600, pat hayes wrote: >>RDF Semantics document, >>last call version, 23 january 2003 >>This comment was mailed earlier to the WebOnt WG [1]. > >For the record, the editor accepts this as an editorial comment. > >>The definition of subinterpretation I << J in Appendix B >>is not clear, as >>it is not clear what a "projection mapping from IR into JR, >>IS into JS, IL into JL and IEXT into JEXT" is. >>IR and JR are sets, so the first part is clear: a function >>from IR into JR. However, IS and JS are functions. >>(What is meant by a mapping from a function to a function?) > >The concept is a familiar one in mathematics: it is often referred to as a >morphism between functional categories. > >But the wording of the proofs of lemmas will be clarified and this >definition made more explicit. > >>It seems that the following definition suits the intended >>use in the Herbrand lemma: >> >>I is a subinterpretation of J, I << J, when there is a projection >>mapping f : IR -> JR such that the following hold: >>- f(IP) subsetof JP [this is needed for the last condition] >>- for each v in V, JS(v)=f(IS(v)) >>- for each typed literal l, JL(l)=f(IL(l)) >>- for each p in IP, >>{ <f(x),f(y)> : <x,y> in IEXT((I(p)) } subsetof JEXT(f(p)) >> >>Then, automatically, the property that is desired in the text >>follows: any triple is true in J if it is true in I. > >Yes, quite, that is the intent of the current phrasing, stated in a >lengthier form. > >There is an editorial issue generally in writing such things as this >appendix. In many people's view, a document like this should not even have >things like lemmas and proofs in it *anywhere*. To anyone trained in >formal logic these results and the proof techniques are all elementary in >any case. On balance, therefore, it seemed appropriate to give an >expository outline of the basic proof techniques as an informative guide >for some readers as well as providing others (such as yourself, Herman) >with the opportunity to check the reasoning. However, to write out these >proofs too formally and in too much detail does not seem appropriate, as >this would make them unreadable by the novice and boring to the initiated. > >I will try to make the wording clearer, however, in the light of your >comments. > >Pat >-- >--------------------------------------------------------------------- >IHMC (850)434 8903 or (650)494 3973 home >40 South Alcaniz St. (850)202 4416 office >Pensacola (850)202 4440 fax >FL 32501 (850)291 0667 cell >phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes >s.pam@ai.uwf.edu for spamReceived on Tuesday, 25 February 2003 09:36:55 UTC

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