Wikidata:WikidataCon 2017/Notes/Ontology Cleanup

Title: Class Hierarchy Cleanup Workshop

Note-taker(s): Thiemo

Speaker(s)

Name or username: Arthur Smith - User:ArthurPSmith

Contact (email, Twitter, etc.): arthurpsmithgmail.com

Useful links

https://www.wikidata.org/wiki/Wikidata:WikiProject_Ontology/Problems

https://www.wikidata.org/wiki/Help:Basic_Membership_Properties

Abstract

Wikidata has a class hierarchy via the instance of (P31) and subclass of (P279) properties, but often these are applied inconsistently. Some of the most obvious problems are listed under Wikidata:WikiProject Ontology/Problems, but many other issues have been raised in Project Chat and elsewhere. In this workshop participants will discuss these problems and how to fix them, and will take charge in executing those fixes either immediately or in subsequent days depending on the scale of the fix required.

Collaborative notes of the session

Introducing how classes work in Wikidata.

Subclass of (P279) is transitive. Instance of (P31) is not.

Examples are shown and explained.

Circles are explained as a top problem. SPARQL queries to find them are shown.

Classes with more than 1000 subclasses could hint at problems.

Stuff that is an instance of and a subclass of the same thing the same time.

Questions / Answers

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