Talk:Q754673

Class vs instance

In what sense is this a subclass of alphabet, and not an instance of alphabet? Is there a reference for that? --Denny (talk) 19:28, 10 April 2015 (UTC)

• Denny: The external reference hosted at stanford.edu is listed at Help:Class_or_instance#Type-token_space-time_approach IP-80.134.90.212 (talk) 21:10, 10 April 2015 (UTC)

I don't see the linked reference on stanford.edu supporting that the English alphabet is a subclass of alphabet. Can you please explain in what sense this is the case, and find a reference for that statement?, nor that it is a subset of alphabet. Can you find a reference for "the English alphabet is a subset of alphabet"? --Denny (talk) 21:38, 10 April 2015 (UTC)

Denny:

• I cannot find a reference for "the English alphabet is a subset of alphabet"
• From stanford.edu and the page deleted after an attack by User:Succu, it follows that types (classes in Wikidata) are abstract not located anywhere in space-time and tokens (instances in Wikidata) are. The English alphabet has not located anywhere in space-time. Thus it is a class. IP-80.134.90.212 (talk) 22:03, 10 April 2015 (UTC)

„deleted after an attack”? Your are boring. --Succu (talk) 22:07, 10 April 2015 (UTC)

Your mapping of what you understand as instances and classes to types and tokens according to the Stanford article does not fit with the understanding of the Wikidata community. Harry Potter is a valid instance, and so is Hydrogen, and so is the English alphabet. Space-timeness is not a necessary condition for items in order to carry P31. In Wikidata, classes and instances are not even disjoint. --Denny (talk) 22:27, 10 April 2015 (UTC)

Please see Wikidata_talk:WikiProject_Alphabet#Basic_structure_for_letters. The request for references seems one-sided -- is there a reference for the English alphabet being an instance of alphabet, and not a subclass of alphabet? The linked 'Basic structure for letters' discussion suggests that reliable sources tend to classify such things via subclass of, not instance of. Based on rationale laid out in that discussion, I have added a reference for the English alphabet being a subclass of Latin alphabet (and thus a subclass of alphabet). I would ask discussants here to engage in Wikidata_talk:WikiProject_Alphabet#Basic_structure_for_letters and reach consensus there before removing that claim.

Also, the assertion that hydrogen is an instance is somewhat vague. All classes are trivially also instances (they are instances of rdfs:Class or owl:Class), and any class that has an object property (e.g. oxidation state 1) is syntactically interpreted as an instance. Few disagree that hydrogen can be interpreted as an instance in a syntactic sense or in the context of punning / metamodeling. However, the claim "hydrogen instance of chemical element" is questionable, as described in detail at Talk:Q556#Emw_reply_2015-04-12. The mapping of classes and instances to types and tokens is not universally applicable (cf. metaclasses and information artifacts), but it does have precedent in major Semantic Web ontologies, and tends to be a general rule when classifying material entities (apart from metamodeling). Emw (talk) 22:08, 12 April 2015 (UTC)

Discussion ongoing on Wikidata_talk:WikiProject_Alphabet#Basic_structure_for_letters. --Denny (talk) 17:19, 14 April 2015 (UTC)