LC3 Responses/LS1

To: selmi_luigi@hotmail.com
CC: public-owl-comments@w3.org
Subject: [LC response] To Luigi Selmi

Dear Luigi,

Thank you for your comment
     <http://lists.w3.org/Archives/Public/public-owl-comments/2009Sep/0031.html>
on the OWL 2 Web Ontology Language last call drafts.

Regarding reflexivity of the subclass relationship, whether or not the phrase in question is illustrative or confusing seems to be a matter of editorial judgement. We believe that it does more good than harm and so propose to keep it.

Regarding the use of verb forms to indicate the directionality of a relationship, we agree that it is not fool proof, but it is often useful and is very common practice amongst experienced modellers. In fact most modelling tools and "human readable" syntaxes use frame-like or infix notation, which works well with the suggested verb forms.

Thank you for the suggestion regarding regarding natural language indicators for existential quantification -- we have made the relevant addition (see [1]).

Finally, regarding inverse functional properties, it is not the case that only a functional property can be inverse functional. Consider, for example, "isMotherOf" -- this property clearly isn't functional (a mother may have many children), but it is inverse functional (a child has only one mother).

[1] http://www.w3.org/2007/OWL/wiki/index.php?title=Primer&diff=25887&oldid=25821

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Regards,
Ian Horrocks
on behalf of the W3C OWL Working Group

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as a reader of the primer and not as a master of OWL I woul suggest
some minor changes in order to make the document more understandable:

1) paragraph 4.2 where is written :<Besides this, it is also
reflexive, meaning that every class is its own subclass – this is
intuitive as well since clearly, every person is a person etc.. > i
would eliminate "this is intuitive as well since clearly, every person
is a person etc" since it could be confusing rather than illustrative

2) paragraph 4.4 where is written: <names might be constructions with
“of” or with “has” (wifeOf or hasWife). For verbs (like “to love”) an
inflected form (loves) or a passive version with “by” (lovedBy) would
prevent unintended readings. > property label constructed appending
prepositions like in wifeOf or lovedBy is questionable. It doesn't
avoid the possibility of a mistake. See for example the OWL/XML Syntax
of the wife relationship between Bill and Mary. What about using
Andrea instead of Bill. Who is the wife ?. A modeler that needs to
state that two persons are in a "wife" relationship probably creates
two disjoint classes, Man and Woman with the first class as the domain
and the second its range so avoiding all possible confusion.  See for
example what TBL write about this issue here

3) paragraph 5.2 Maybe can be added the line <Natural language
indicators for the usage of existential quantification are words like
"one" or “some” >

6) paragrafo 6.1 where is written: <it is also possible to indicate
that the inverse of a given property is functional > maybe it means
"it is also possible to indicate that the inverse of a given
functional property is functional too"