From: Alan R. <ala...@gm...> - 2014-08-29 20:36:50
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On Fri, Aug 29, 2014 at 10:44 AM, Barry Smith <phi...@bu...> wrote: > Re: the issue raised by: > > oxygen-18 > * subclass of* oxygen > *instance of* isotope > > can I ask that people help me get clear about the background: > > (a) is it the case that all of these expressions refer to general entities > which have many many particular instances > yes (b) is it the case that every instance of oxygen-18 is also an instance > of isotope > to be an isotope is something like to be a mutation. To be a mutation is to be slightly different from the canonical, but of equal status except for perhaps the number of class members. To be an instance of an isotope of oxygen (atom) is to be a an atom with a different number of nucleons (protons and neutrons) than the most abundant form (oxygen-16, with 8 protons and 8 neutrons in its nucleus). One might argue that the number of nucleons is a quality of anything oxygen, of which I list a variety of entities that ChEBI represents in an earlier message. > (c) if yes, then why not just assert 'subclass of' throughout? > You can, just as you can say that red balls are a subclass of colored things ;-) -Alan > > > BS > > > > ------------------------------------------------------------------------------ > Slashdot TV. > Video for Nerds. Stuff that matters. > http://tv.slashdot.org/ > _______________________________________________ > Chebi-ontology mailing list > Che...@li... > https://lists.sourceforge.net/lists/listinfo/chebi-ontology > > |