Wikidata:Property proposal/quantity symbol

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quantity symbol (mathematical expression)[edit]

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   Under discussion
Descriptionsymbol for a mathematical or physical quantity
Representsquantity symbol (Q1401551)
Data typeMathematical expression
Domainindividual quantity (Q71550118)
Example 1electric charge (Q1111) → Q
Example 2group velocity (Q217361) → c_g
Example 3mass fraction of water (Q76379025) → w_{H_2O}
Example 4area density (Q1907514) → \rho_A
SourceISO/IEC 80000 (Q568496)
Planned usereplace quantity symbol (P416)
Number of IDs in sourcehundreds
Expected completenessalways incomplete (Q21873886)
See alsounit symbol (P5061)


The existing quantity symbol (P416) has datatype string, which is not sufficient to represent all the notation used for quantity symbols. While there are some Unicode (Q8819) sub- and superscripts, they are often not appropriate for use in quantity symbols (usually, special Unicode symbols are tied to a particular use); not all letters are available and nesting of subscripts is not supported (see example 3 above) Toni 001 (talk) 21:50, 26 November 2019 (UTC)


  • Symbol support vote.svg Support David (talk) 05:34, 27 November 2019 (UTC)
  • Symbol support vote.svg Support Swpb (talk) 14:20, 27 November 2019 (UTC)
  • Pictogram voting comment.svg Comment @Toni 001: Your proposal also uses datatype string. Did you mean to have type "mathematical expression"? Are you proposing to remove all uses of quantity symbol (P416) and replace it with the new property? If not we need a distinctive label for this property... ArthurPSmith (talk) 19:18, 27 November 2019 (UTC)
    • @ArthurPSmith: Thanks for the hint. Yes, it should be "math"; fixed now. (I remember entering math while working on this proposal and I even checked that the link works; not sure what happened.) Yes, this should completely replace P416 - there won't be any use (that I could think of) for the other property. I've been wondering how we deal with the property name in the transition period (as there are less than 300 values I expect only a few days - I volunteer to move them manually and check and improve them in the process). Maybe the new property could temporarily have some parenthesis like "(replacement for P416)" in either the label or description. Toni 001 (talk) 12:21, 28 November 2019 (UTC)
    • Ah, the datatype was changed in this edit. Toni 001 (talk) 12:23, 28 November 2019 (UTC)
  • Pictogram voting comment.svg Comment this will not be created until we agree on a new label: two properties cannot have the same label in the same language. − Pintoch (talk) 15:50, 4 December 2019 (UTC)
    • Anyone have a problem with labeling this "quantity symbol (mathematical expression)" and changing the old one to "quantity symbol (DEPRECATED)"? This is just until the uses are migrated, after all. Swpb (talk) 17:33, 4 December 2019 (UTC)
      • @Swpb: Yes, that sounds good to me. @Jura1: I noticed you already added (Tex), thanks. I updated it to (mathematical expression) as it is called like this in the documentation. Toni 001 (talk) 13:19, 5 December 2019 (UTC)
        • Maybe we could use "LaTeX" as at title in LaTeX (P6835). With "(mathematical expression)" it can be misunderstood as not meaning the datatype. --- Jura 13:46, 6 December 2019 (UTC)
    • I think it could actually be helpful to have both. math datatype is still incompletely supported and it's not clear if that ever will change. Many basic things can still not be done. --- Jura 04:48, 5 December 2019 (UTC)
      • @Jura1: With "incomplete support" are you suggesting that there are things that can be entered as string but not as math? From my limited experience I would guess that the new property can do more than the old one - in particular, all the values I've seen for the old property can definitely be expressed with the new one. Toni 001 (talk) 13:22, 5 December 2019 (UTC)
        • Not quite, anything can be entered in either, it's just that the math version can't be queried reliably on Query Server.--- Jura 18:49, 5 December 2019 (UTC)
  • Symbol support vote.svg Support. Wikisaurus (talk) 20:33, 5 December 2019 (UTC)
  • By the way, how one should label language? For example, median lethal dose (Q711849) is called "LD50" in most languages, but "DL50" in French (also "ЛД50" in Russian and Ukrainian, but they probably use international "LD50" quite often, so "LD50" is ok for them). Is it normal what is done on p:P2240#P416? (I know it should not be on the property). Wikisaurus (talk) 13:40, 6 December 2019 (UTC)
    • @Wikisaurus: A similar question has been raised before for unit symbol. So in the long term, we might potentially want a hybrid datatype that is both "mathematical expression" and "monolingual text". Or we could try to model this with qualifiers as intended in the example you gave. Toni 001 (talk) 14:04, 6 December 2019 (UTC)