Property talk:P361

Documentation

part of
object of which the subject is a part (if this subject is already part of object A which is a part of object B, then please only make the subject part of object A). Inverse property of "has part" (P527, see also "has parts of the class" (P2670)).
Description This item is a part of that item; expresses a whole-part relationship. Opposite of has part (P527). part (Q15989253) Item Any (note: this should be moved to the property statements) Any (note: this should be moved to the property statements) https://www.wikidata.org/wiki/Help:Basic_membership_properties Anerebel (Q7362) → head (Q23640)ecosphere (Q3175157) → biosphere (Q42762) http://www.w3.org/2001/sw/BestPractices/OEP/SimplePartWhole/ Consistency should be checked with proposed property, e.g. "whole thing of" (holonime). no label (Q42533292) Category:Pages using Wikidata property P361 (Q23909016) member of (P463), parent organization (P749), part of the series (P179), facet of (P1269), found in taxon (P703), culture (P2596), partially coincident with (P1382), business division (P199), CITES Appendix (P7603) Proposal discussion 2,047,088
[create] Create a translatable help page (preferably in English) for this property to be included here
 Conflicts with “instance of (P31): Wikimedia category (Q4167836), Wikidata property (Q18616576)”: this property must not be used with the listed properties and values. (Help)Exceptions are possible as rare values may exist. List of this constraint violations: Database reports/Constraint violations/P361#Conflicts with P31, SPARQL, SPARQL (new)
 Allowed entity types are Wikibase item (Q29934200): the property may only be used on a certain entity type (Help) List of this constraint violations: Database reports/Constraint violations/P361#allowed entity types, hourly updated report, SPARQL (new)
 Non-list part of list Item that is not a Wikimedia list article part of instance of a Wikimedia list article (Help)Violations query: SELECT ?item WHERE { ?item wdt:P361 / wdt:P31 wd:Q13406463. FILTER NOT EXISTS { ?item wdt:P31 wd:Q13406463 . } }List of this constraint violations: Database reports/Complex constraint violations/P361#Non-list part of list
 Value Travelers, season 1 (Q49799279) will be automatically replaced to value Travelers, season 1 (Q49799279) and moved to season (P4908) property.Testing: TODO list
 Value Travelers, season 2 (Q49799400) will be automatically replaced to value Travelers, season 2 (Q49799400) and moved to season (P4908) property.Testing: TODO list
 Value Travelers, season 3 (Q59766627) will be automatically replaced to value Travelers, season 3 (Q59766627) and moved to season (P4908) property.Testing: TODO list

Usage note

Usage is detailed in Help:Basic membership properties.

Discussion

Usage note

For publications, like articles published in a journal, please use the more accurate term published in (P1433). See also: Help:Sources. --Kolja21 (talk) 10:09, 27 July 2014 (UTC)

Q5325

Is this property really intended to be used like in Q5325? Inductor is part of Electronic circuit? I mean it is not a fixed part of an electronic circuit... --Faux (talk) 08:26, 30 March 2013 (UTC)

I think the relevant property would be P:P366 (use). --Zolo (talk) 05:25, 1 April 2013 (UTC)

Direct part?

Just to be clear about this property, does "part of" mean "direct part of"? For example, if "A part of B" and "B part of C", then A is not a direct part of C, but an indirect one. I would prefer that this property be used in the direct sense because the indirect sense can always be inferred. Silver hr (talk) 05:02, 31 March 2013 (UTC)

Yes. This property is transitive. So in cases like "A part of B" and "B part of C", the claim "A part of C" is extraneous and should not be made. Emw (talk) 05:15, 31 March 2013 (UTC)

Neutrons

Related to Q5325 above. Should this property be used only when the object is always part of the whole ? As neutrons sometimes exist outside atoms, how should we, I would have assumed that this property should not be used, and that we should have something like "atom nucleus is composed of protons and neutrons". But "composed of" would be harder to deal with than "part of", so that may not be the best solution either. --Zolo (talk) 05:01, 3 April 2013 (UTC)

• I have been thinking about this issue too, actually I intentionally avoided this problem in Help:basic membership properties by using the example "quark is part of hadron" instead of examples like "electron is part of atom" because there are no free quarks (at least not discovered yet). I still don't know how to deal with this issue, but I think there are several situations here (assume X, Y are classes):
• ${\displaystyle (\forall x\in X)(\exists y\in Y),x{\text{ is part of }}y}$
• ${\displaystyle (\forall y\in Y)(\exists x\in X),x{\text{ is part of }}y}$
• ${\displaystyle (\exists x\in X)(\exists y\in Y),x{\text{ is part of }}y}$
It's more natural to say "part of" for the first situation, and more natural to say "composed of" (or "has part") for the second situation. The problem is should we and if so how do we distinguish these different situations? --Stevenliuyi (talk) 17:35, 3 April 2013 (UTC)
• This property is transitive, so using it only when the subject part is always part of the object whole would be the safest option. The relevant W3C document and Semantic Web implementations I've seen distinguish between 'part of' and 'has part' properties. We shouldn't conflate these two properties, since they're inverses of each other and conflating them would lead to contradictions. That said, while I think it's important to not confuse 'part of' and 'has part', the following quote from that W3C document makes me wary of creating a 'has part' property:

"Unfortunately, all current OWL reasoners scale very badly for large part-whole hierarchies connected by both hasPart and partOf. Therefore, if reasoners are to be used, it is usually necessary to choose to use either partOf or hasPart but not both. Often it is preferable to use partOf because the most common queries and class definitions are for the parts of things, e.g. the class of all parts of a car." Simple part-whole relations in OWL Ontologies

The case represented by Stevenliuyi's third expression is an important type of whole-part relation. This expression would describe how neutrons can exist as parts of atoms or not. Would a qualifier for "part of" claims like "can be" be a reasonable way to enable that kind of expression?
Finally, I figured I'd point out that representing part-whole relations doesn't seem to be a solved problem in ontology. Figure 1 on page 5 of "Representing and reasoning over a taxonomy of part-whole relations" shows how "part of" can take on several different meanings. Emw (talk) 03:04, 4 April 2013 (UTC)
Thanks, I'll try to have a closer look at the links. Just thinking aloud, maybe we could do something with a qualifier taking "all", "some" or "none" as values. All cases would be covered with two properties ("part of" and "composed of") + qualifier, and that might be of use for some other properties as well. --Zolo (talk) 15:55, 8 April 2013 (UTC)

Stevenliuyi, I noticed that you left out ${\displaystyle (\forall x\in X)(\forall y\in Y),x{\text{ is part of }}y}$, while I thought it was the most obvious usecase (in particular with both X and Y unique; like in the UN Security Council is part of the United Nations). Do you think it should use a different property ? --Zolo (talk) 10:51, 27 April 2013 (UTC)

I guess you mean use cases like "flight deck is part of aircraft carrier". If so, actually the expression ${\displaystyle [(\forall x\in X)(\forall y\in Y),x{\text{ is part of }}y]}$ is incorrect since every single flight deck can only be part of one aircraft carrier, it can't be part of every aircraft carrier (it's correct if and only if X and Y are unique). The correct expression is ${\displaystyle [(\forall x\in X)(\exists y\in Y),x{\text{ is part of }}y]\wedge [(\forall y\in Y)(\exists x\in X),x{\text{ is part of }}y]}$, which means it meets both the first and the second case I metioned above. So I think this property works fine in such situations.--Stevenliuyi (talk) 12:28, 27 April 2013 (UTC)
Oops, sure, sorry. Still, I was mainly thinking about the case where there is just one X and one Y, because it makes both "is part" and "has part" really transitive, but as we have not really solved the transitivity issue for the ascending (is part) direction, that was not really a relevant point to raise ;). --Zolo (talk) 13:18, 27 April 2013 (UTC)

'except' qualifier

Would an 'except' qualifier for 'part of' be useful for cases like this, where some item is part of a certain class A except a small collection of A's? For example, neutrons are part of all elements except certain types of hydrogen. Here's how a claim might look:

Of course, this claim isn't completely precise. Certain types of neutrons (free neutrons) aren't part of any atom elements. Would this problem be feasible to solve by creating new items 'bound neutron' and 'free neutron', both subclasses of 'neutron', and putting the 'part of chemical element except hydrogen atom' on 'bound neutron'? Emw (talk) 03:04, 1 May 2013 (UTC)

It seems like a sensible complementary to part concerned. My (somewhat random) guess is that "part concerned would be slightly easier to use but that both can be useful. --Zolo (talk) 16:50, 12 May 2013 (UTC)

implicit quantification

Did we reach any conclusion about the questions above? It seems to me that a relation like "is part of" is inherently an individual-level property (e.g. China is part of Asia). Once you start using it between classes (e.g. neutrons are part of nuclei) then what you're really doing is making an implicitly quantified statement, which really expands to one those listed above by Stevenliuyi. Maybe we could address this by adding a qualifier (e.g. "quantification") with values like "all exists", "exists all", "all exists unique". See Cyc's type-type rule macro predicates for more examples. Bovlb (talk) 13:00, 15 October 2015 (UTC)

@Zolo, Emw: Bovlb (talk) 00:12, 19 October 2015 (UTC)

Use for individuals who've been members of certain bodies

Currently Q76 lists Barack Obama as "part of" the various legislative bodies he served in. I don't think that's really what this property is for—the U.S. Senate seats from Illinois are part of the U.S. Senate, but I don't think the same applies to individual Senators (and ex-Senators). Thoughts? — PinkAmpers&(Je vous invite à me parler) 01:02, 8 May 2013 (UTC)

Technically the usage is correct, but I think we should use office held in this case. I can't find suitable items, maybe we could create items such as "United States Senator" (with qualifier to indicate he represented Illinois) and "Member of the Illinois Senate" (with qualifier to indicate he represented the 13th District).--Stevenliuyi (talk) 01:24, 8 May 2013 (UTC)
That sounds like a good way round to do that. James F. (talk) 20:44, 9 May 2013 (UTC)

Reverse property?

Romulus is part of Romulus and Remus, but in opposite direction? How to say, that ROmulus and Remus have part Romulus and part Remus? I am not able to find such property. JAn Dudík (talk) 18:30, 16 May 2013 (UTC)

Looks like P:P150 is reserved for administrative division, Aaarghhh!!! Looks like I have to redo in some places. This "administrative"-thing gives me headache. It looks good in theory but fails when reality comes... -- Lavallen (block) 19:07, 16 May 2013 (UTC)
P527. 12:34, 17 May 2013 (UTC) has part (P527)
!!! -- Lavallen (block) 15:14, 17 May 2013 (UTC)

Vagueness

Surely this is plain wrong? This is quite a strict concept... Littledogboy (talk) 14:19, 26 July 2013 (UTC)

constraint report relating to Wikimedia disambiguation page (Q4167410)

If instance of (P31) is a Wikimedia disambiguation page (Q4167410) the presence of part of (P361) is prohibited

see: Wikimedia disambiguation page (Q4167410) with part of (P361) . Usualy there might be two possibilities:
a) please identify the non - ambiguation page (WD item) where the property part of should be moved;
"normally" no other statements should be left at the disambiguation page;
it can happen that a set of properties should be moved to another (a second) WD item, another set to a third WD item etc.
b) verify which language is a disambiguation page and separate it from the rest; please use Gadget-labelLister.js can be activated at preferences#gadgets to remove all faulty descriptions after the disambiguation page is separated (the languages are de, en, fr, es, pt, pt-br, ru, sv and possibly some others).

Thanks in advance! gangLeri לערי ריינהארט (talk) 13:32, 23 May 2014 (UTC)

Is everything part of the universe?

Should part of (P361) always have an unbroken chain to Universe (Q1), like how instance of (P31)/subclass of (P279) are required to always have a chain to entity (Q35120)? --Yair rand (talk) 14:04, 28 April 2015 (UTC)

Depends. I would tend to agree that either 361 or its inverse should have some chain. Immediately my concern is how we handle fictional entities which are not themselves in this universe but which are ideas made in this universe. There are other similar ones, such as the notion of a "multiverse" (which clearly has part universe but which the notion of a universe is gestated inside the universe...). @emw: might have an interesting thought or two. --Izno (talk) 17:09, 28 April 2015 (UTC)
A fictional entity could be part of a book or story, which could be part of human literature, which could be part of human ... culture? Not sure how it would be categorized, but there's probably a broader concept that it's part of. Multiverse presents an interesting difficulty, and I'm not sure how to work that out. If necessary, perhaps existence (Q468777) or everything (Q2165236) could be used instead of Universe (Q1). I suspect that it would be possible, if difficult, to attach all items to a large chain, but I'm not at all sure it would be good/worthwhile to do so. --Yair rand (talk) 18:17, 28 April 2015 (UTC)
Another thought: for some things (predominantly the general class of things we call "products" in my mind), it's better to use the reverse relation has part (P527) example "macaroni and cheese" has part "macaroni" and "cheese" since this is a much smaller set of relations to maintain on a particular item's page than the inverse (you can imagine how many things "cheese" is a part of (P361))...). So a chain of part of or has part all the way in some direction isn't sensible. Maybe there are some items where it makes sense to say both has part and part of to be a "link" in the middle from which you can extend up or extend down. --Izno (talk) 19:31, 28 April 2015 (UTC)
I don't think that non-concrete things are really part of the "universe", which is concrete in nature. So "idea", "concept", "religion", "God", "economy", "socialism", "politics", "law", "religion", "history", "story", "poem", "science", "measurement", "metre", "mathematics", "addition", "zero", "negation", "formula", "name", "toponym", "antonym", "language", "geography", "demography", etc. are not part of the "universe", unless you use a very broad definition which is not associated to the cosmology.
In addition, "universe" is not the root: "universe" is part of "nature", still a large concrete thing but also an abstract concept, which partly includes various (related) abstract things, including: "biology" or "biology" which are themselves part of "science", which also contains "social sciences" containing "history" or "economy", or "theology" containing "religion" or "mythology").
It is in fact difficult to determine what would be a good "root", and in fact in Wikimedia we've identified at least four distinct roots because we are unable to choose between them:
• "nature"
• "society" (containing "politics", "religion", "legal topics", "economy", "people", "organisations", "countries", "education")
• "culture" (containing "religion", "history", "art", and some parts of "society" such as "education"),
• "science and technology" (only partly covered by "society" or "nature" or "culture", but including "geography", "geology", "demographics", "mathematics").
Verdy p (talk) 11:28, 25 February 2016 (UTC)

Usage for (sub)branches of science(s)

I'd like to know the reasoning behind this property's wide use for modelling the (sub)branches of science. For example, pharmaceutical science (Q7180763) is part of (P361) biology (Q420), but biology (Q420) does not has part (P527) pharmaceutical science (Q7180763) (even though there's an inverse constraint...). There are many other such cases, and it's also true for mathematics (like "geometry" is part of "mathematics", but apparently "mathematics" has part "area of mathematics") and other technical specialities modelled on Wikidata, so it seems quite popular. Why not use subclass of (P279)? Why was it decided that is bad? --BurritoBazooka (talk) 22:28, 25 September 2015 (UTC)

Note: My first example above wasn't true in the database a few minutes ago, it used to be the case that "pharmacology" is a direct part of "biology" (but, again, not the other way around). I moved "pharmacology" further down with "pharmaceutical sciences" as its parent. --BurritoBazooka (talk) 22:32, 25 September 2015 (UTC)
Same for industries. I find it difficult to decide whether industries are composed of other industries or industries are subclasses. Inheritance or composition. What to choose? --Vanuan (talk) 21:12, 5 September 2016 (UTC)

"Part of" tree

I threw together a tool that shows much of the "part of" tree for items, including many implied statements. (This works under the assumption that X>instance of>Y>part of>Z implies X>part of>Z.) This brings up some strange statements... --Yair rand (talk) 04:03, 30 November 2015 (UTC)

shouldn't this property be reflexive like "subclass of" ?

Isn't any (instance of an) item a part of itself? Also for the inverse: Doesn't any (instance of an) item have itself as a part? DavRosen (talk) 00:11, 11 February 2017 (UTC)

@DavRosen: No? I'm not sure why you would think it would. --Yair rand (talk) 23:43, 13 February 2017 (UTC)
@Yair rand: Why is subclass of (P279) an instance of reflexive property (Q18647521)? Isn't it because every class is a subclass of itself, unless subclass is further specified as a strict or proper subclass, i.e. "subclass smaller than the class itself", like the meaning of proper subset or strict subset? I just thought "part of" might have the same characteristic, unless it implicitly means "part of, but less than the whole". (edit) DavRosen (talk) 13:31, 14 February 2017 (UTC)

Part of more than one entity?

The definition "object of which the subject is a part" suggests an entity should have zero or one P361 properties. Is that right? For example, Russian Air Force (Q209833) claims the entity is part of two other entities (and the second of those is part of the first). But if my naive concept of zero or one is correct, how is it possible to enter more than one? At any rate, I'm investigating an error at c:Category:Air force of Russia which currently is showing 'part of: The ID "Q193159 and Q21042210" is unknown to the system. Please use a valid entity ID.' Johnuniq (talk) 01:17, 10 September 2017 (UTC)

Removing inverse constraint

Given the current usage of part of (P361) I see that it's frequently used in cases where one thing might have 1000 or more parts. In those cases we don't want to have all entries listed in both directions. I therefore suggest removing the inverse constraint.

Notified participants of WikiProject Ontology Notified participants of WikiProject property constraints ChristianKl () 19:00, 17 December 2017 (UTC)

Items with most P527 and items with most P361. It’s not that bad, definitely not “frequently used” in such cases. Since the “inverse constraint” is useful in many other cases, it tend to oppose this request. —MisterSynergy (talk) 19:10, 17 December 2017 (UTC)
Ie, there are no rules in WD, but is there a subjective approach? Do we want or do not want? So this is called original research. --Fractaler (talk) 06:24, 18 December 2017 (UTC)
I support removing the constraint because part of (P361) is the inverse of has part (P527) and has parts of the class (P2670) combined. --Pasleim (talk) 10:27, 18 December 2017 (UTC)
I agree with Pasleim. Sjoerd de Bruin (talk) 10:42, 18 December 2017 (UTC)
Seriously, so if [Paris, New York, …] have parts of type house, this means that « house » part of (P361) « Paris » make sense ???? I don’t think it works at all. author talk page 17:11, 18 December 2017 (UTC)
An individual house is supposed to have located in the administrative territorial entity (P131) to something that's located in the administrative territorial entity (P131) Paris (maybe with steps in between). located in the administrative territorial entity (P131) inturn is a subproperty of part of (P361). part of (P361) and located in the administrative territorial entity (P131) are both transitive. ChristianKl () 16:37, 19 December 2017 (UTC)
@MisterSynergy: Can you explain what you mean with "useful" more specicially? What use do you draw from the constraint existing? ChristianKl () 16:23, 19 December 2017 (UTC)
This query highlights much better the difficult cases than the ones before. The ?diff variable indicates roughly how many constraint violations each of these cases produces. However, surprisingly often P361/P527 does not seem to be the best choice at all, thus the constraint violations can be indicative of a bad property choice in the affected statements. This property pair has already gone downhill for a while unfortunately in that we use it for all kinds of somewhat related stuff (regardless whether there is a true part of/has part relationship), so should better not support bad property use by removing constraints that indicate problematic use. —MisterSynergy (talk) 19:50, 19 December 2017 (UTC)
The property is used a lot and it makes sense to replace many uses with more specialized proerties but I don't see how the constraint helps with that. ChristianKl❫ 16:26, 25 December 2017 (UTC)
As far as I know we will have the constraintCheck gadget activated by default for all users soon, which means that the violation will show up in each an every affected item. This makes the problem of bad property choice very visible; useful constraints such as this one guide users to model data properly instead of using some generic properties over and over again until they are effectively meaningless. As I already said, this one and its inverse counterpart are already in bad shape, unfortunately, and this inverse requirement is one of the last barriers before it became completely useless. --MisterSynergy (talk) 20:52, 25 December 2017 (UTC)
In many cases we don't have a specialized property that's more precise than part_of/has_part. ChristianKl❫ 23:11, 25 December 2017 (UTC)
This is yet another improved version of the query, now including labels for better evaluation. There is Wikidata:Property proposal if nothing fits, which may be a case for the many "protein superfamily" relations. Most others can already be fixed with existing properties. I really do not see a need to remove this valuable constraint for a very small number of cases with many constraint violations. --MisterSynergy (talk) 09:56, 26 December 2017 (UTC)
Comment One example of asymmetric “part of” links can be found in WD:WikiProject Stolpersteine – we claim that individual stumbling stone (Q26703203) objects (e. g. Stolperstein dedicated to Mildred Harnack (Q26703202)) are all , but we cannot possibly add all the inverse claims to Stolpersteine (Q314003), there are way too many objects. The only solution other than removing this constraint would be some improved exception system where we would only need to record the exception Stolpersteine (Q314003) once, not for every individual stumbling stone (Q26703203) object. --TweetsFactsAndQueries (talk) 13:12, 18 December 2017 (UTC)
Given that I get a ping for every new Stolperstein, it was also the top item on my mind. ChristianKl () 16:23, 19 December 2017 (UTC)
•  Support No need for both sides to be specified in most cases I think; maybe some guidelines on when it's best to put the relationships on one side or the other would be good...? ArthurPSmith (talk) 14:03, 18 December 2017 (UTC)
• @MisterSynergy:Including myself I see 4 people supporting the removal and only one (you) advocating keeping it. Do you think that's not consensus? ChristianKl❫ 16:26, 25 December 2017 (UTC)
• As long as the constraint is there, I'll just add exceptions as I find them. For a start, university hospital (Q1059324) is part of a university (Q3918), but the reverse doesn't necessarily apply. Ghouston (talk) 09:43, 22 April 2018 (UTC)
• Note that the inverse property has part (P527) doesn't have the constraint. Ghouston (talk) 09:45, 22 April 2018 (UTC)
•  Comment It looks like the constraint was removed per the above discussion, and then re-added. I am removing it again - please see this discussion, and let's keep this constraint off or it leads to massive inappropriate actions of this sort. ArthurPSmith (talk) 17:19, 25 June 2018 (UTC)
• I don't see that it's always a mutual relationship. However, it may depend on exactly how you interpret the claim. Would it make any sense to say that a wheel is part of a wheeled vehicle, when you can have pottery wheels, wheels inside machines, or just wheels fresh off a production line? When we say "part of", do we mean "is sometimes part of" or "can potentially be part of"? Ghouston (talk) 00:19, 26 June 2018 (UTC)
• Or at least, when you are talking about specific items, I can say that that particular car door is a part of that car, and vice versa the car has the door as a part. But I can't logically say that car doors in an abstract sense are always part of a car, since there are cars without doors and car doors without cars. Ghouston (talk) 00:21, 26 June 2018 (UTC)
• Also, see the discussion that User:ArthurPSmith linked to above, which shows that in some cases it's not possible to add the claim on both sides, due to technical limitations. One side or another should be sufficient, as long as it's always done the same way in a particular situation. Ghouston (talk) 00:29, 26 June 2018 (UTC)

Bands

Hello, what property must be used with persons that belongs to a music band? For example Freddie Mercury (Q15869) is member of (P463) Queen (Q15862) and Paul McCartney (Q2599) part of (P361) The Beatles (Q1299) and he is member of (P463) American Academy of Arts and Sciences (Q463303). Thanks, Juan Mayordomo (talk) 19:23, 14 May 2018 (UTC)

@Juan Mayordomo: In both cases member of (P463), it is more specific for individual humans. Bigbossfarin (talk) 15:02, 22 July 2018 (UTC)
Thanks. Juan Mayordomo (talk) 20:24, 22 July 2018 (UTC)

regarding military units

Should a unit be a "part of" or a "subsidiary of" its higher HQ? - Trilotat (talk) 03:52, 25 September 2018 (UTC)

military branch (P241) is used for that, as long as the parent item is a branch. If it's part of another division of the branch, I'd use subsidiary (P355) as well. Ghouston (talk) 19:45, 2 December 2018 (UTC)

Lists, part of, and the distinction between a name and its referent

Regarding this property and its use with instances of Wikimedia list article (Q13406463) as values: (I've used this analogy before, but it bears repeating.)

Suppose I take a piece of paper and start writing a list. I take a pen and write on the paper "A balloon", and below that "My chair", and at the bottom "My hand". You could say that there is a certain relationship between the paper and my hand.
Then suppose I take a different piece of paper. I write down "A balloon", and then "My chair", and then I staple my hand to the paper.
These two relationships are different from each other.
The part of (P361) relationship is complicated, but a mentioning of one entity's name on another is clearly not it. As such, I'm adding a complex constraint to this property, for all non-list items that have P361 pointing to a list item. Any objections? --Yair rand (talk) 23:21, 10 March 2019 (UTC)

• fine with me. --- Jura 11:42, 16 March 2019 (UTC)

single value constraint

@user:Geertivp I have seen that the value: single value constraint was added to this property. I think this is wrong, as an object (in my cases tram strops) can belong to several items. --GodeNehler (talk) 08:49, 6 August 2019 (UTC)

I agree, and the constraint didn't point to a discussion so I felt free to remove it. --SCIdude (talk) 16:00, 6 August 2019 (UTC)