Wikidata:Property proposal/complementary property

complementary property

Originally proposed at Wikidata:Property proposal/Generic

   Done: complementary property (P8882) (Talk and documentation)

Description	property expressing a aspect of the same relation that completes this property (e.g. start date and end date). The two can be seen as opposites. For inverses, use "inverse property" (P1696). For relations among items, see "opposite of" (P461).
Data type	Property
Domain	Wikidata property (Q18616576)
Allowed values	Wikidata property (Q18616576)
Example 1	start time (P580) → end time (P582)
Example 2	work period (start) (P2031) → work period (end) (P2032)
Example 3	start of covered period (P7103) → end of covered period (P7104)
Example 4	service entry (P729) → service retirement (P730)
Example 5	service retirement (P730) → service entry (P729)
Planned use	add to properties on Help:Dates#Property_pairs_for_time_periods
See also	inverse property (P1696): links a property to its inverse property (which relates the subject and object in reverse order) opposite of (P461): item that is in some way the opposite of this item

Motivation

At Help:Dates#Property_pairs_for_time_periods, there is a list of such pairs. I think it would be good to add it as structured data into Wikidata as well. Please don't hesitate to improve the description and even the label (Add your motivation for this property here.) --- Jura 12:32, 20 November 2020 (UTC)

Discussion

•  Support This seems reasonable to me, and useful. ArthurPSmith (talk) 18:59, 20 November 2020 (UTC)
•  Support --Tinker Bell ★ ♥ 22:47, 20 November 2020 (UTC)
•  Support -- quick question: how will this deal with 1:m relationships? Eg inception (P571) seems to have 4 matched properties. --Hannes Röst (talk) 19:38, 24 November 2020 (UTC)
  • @Hannes Röst: I don't think that's a problem, other than for people to avoid placing constraints on the property that can have many complements to force just one of them. At first I thought even this property was not really necessary because we have related property (P1659), but some problems have a very large number of "see also's" and this is a nice confinement that usually limits it to just one (but not always). ArthurPSmith (talk) 19:20, 25 November 2020 (UTC)
•  Support nice Bouzinac ^{💬●✒️●💛} 11:03, 28 November 2020 (UTC)

 Done as complementary property (P8882) by User:Epìdosis, @ArthurPSmith, Tinker Bell, Hannes Röst, Bouzinac: thanks for your help/support. --- Jura 13:58, 28 November 2020 (UTC)