Wikidata:Property proposal/mathematical symbol

mathematical symbol

Originally proposed at Wikidata:Property proposal/Natural science

   Not done

Description	symbol or notation for a mathematical concept
Represents	mathematical concept (Q24034552)
Data type	Mathematical expression
Domain	mathematical concept (Q24034552)
Example 1	natural logarithm (Q204037) → $\ln x$, $\log _{\mathrm {e} }x$
Example 2	pi (Q167) → $\pi$
Example 3	associated Laguerre polynomial (Q109497177) → $\mathrm {L} _{n}^{m}(z)$
Example 4	imaginary unit (Q193796) → $\mathrm {i}$, $\mathrm {j}$
Example 5	curl (Q206310) → $\nabla \times {\boldsymbol {U}}$, $\operatorname {\mathbf {rot} } {\boldsymbol {U}}$
Example 6	divides (Q109497082) → $m|n$
Example 7	indefinite integral (Q8437543) → $\int f(x)\,\mathrm {d} x$
Source	ISO 80000-2 (Q5974427), Wikipedia
Expected completeness	always incomplete (Q21873886)
See also	notation (P913), quantity symbol (LaTeX) (P7973), unit symbol (P5061), Schläfli symbol (P3228)

Motivation

There's a large number of symbols or expressions consisting of multiple symbols used for mathematical objects like constants, functions, spaces and so on. Let's collect those, starting with common ones like the ones listed in, for instance, ISO 80000-2 (Q5974427).

We already have properties for quantities and units: Those have very specific typesetting rules, which are not applicable in general to other mathematical objects. Take for instance the letter i: When representing a quantity (say, an instantaneous electric current) an italic type is used, while in mathematics, representing the imaginary unit, a nonitalic type is used. Therefore it makes sense to not reuse those for math notation.

For certain objects, say, polytopes, there is a dedicated notation. In that case using a dedicated property is preferred (in this example the Schläfli symbol (P3228)).

Toni 001 (talk) 13:43, 9 November 2021 (UTC)

Discussion

•  Support nice idea Germartin1 (talk) 10:20, 10 November 2021 (UTC)
•  Support Ungurinis (talk) 14:08, 10 November 2021 (UTC)
•  Comment Hmm, I'm not opposed, but isn't this currently handled by a combination of defining formula (P2534) and in defining formula (P7235)? Are there cases this would cover that don't have a defining formula (P2534) value? ArthurPSmith (talk) 18:23, 12 November 2021 (UTC)

  Sometimes there are multiple common symbols. The property proposed here should list all of them (ideally with source so we know who recommends what). If a certain mathematical entity has a defining formula (P2534) then in defining formula (P7235) indicates the (one and only) symbol under which it appear in the formula. So in defining formula (P7235) serves a different purpose. This is completely analogous to how quantity symbol (LaTeX) (P7973) lists all the commonly used symbols for a given quantity.

  (An interesting relation is that typically the value for in defining formula (P7235), if any, should also appear amongst the values of the property proposed here.) Toni 001 (talk) 21:12, 12 November 2021 (UTC)

  To answer your second question, take example 2 from above, pi (Q167): With the property proposed here we'll simply list its symbol, $\pi$. Whether there's a formula which requires an explanation of it's symbols (using P7235) is an independent question. Toni 001 (talk) 21:17, 12 November 2021 (UTC)

  Yeah, ok, I think I see the need. Ok,  Support ArthurPSmith (talk) 22:01, 15 November 2021 (UTC)

•  Oppose redudant to existing properties. --- Jura 16:26, 18 November 2021 (UTC)

  Hm, in the motivation and in reply to ArthurPSmith's comment I explain exactly why this is not covered by existing properties. Could you please elaborate? Toni 001 (talk) 09:06, 19 November 2021 (UTC)

  You might be confusing the concepts of formula and notation/symbol: A formula relates mathematical entities (through equations, equivalences, ...), while notation is a particular way of referring to those mathematical entities on paper (or screen, ...). For instance, $\mathrm {i} ={\sqrt {-1}}$ states that the imaginary unit is the square root of minus one. Someone else might want to use $\mathrm {j}$ for the imaginary unit. Now, how would we model those two things? In the property proposed here we list all the symbols typically used for the imaginary unit, $\mathrm {i}$ and $\mathrm {j}$. But we'd still have just one formula where we pick one notation/symbol to represent the imaginary unit.

  One might be tempted to reuse the formula to indicate different notations, as in $\mathrm {i} =\mathrm {j} ={\sqrt {-1}}$. However, there are issues:

  • A. The first equal sign states nothing, in the sense that both sides refer to the same entity.
  • B. This formula is mixing two concerns: Relating mathematical entities and listing different symbols or notation used for a given entity.

  Toni 001 (talk) 09:39, 6 December 2021 (UTC)

•  Oppose We already now have too many properties for displaying semantics in Wikipedia. Thus adding more options seems counter intuitive. I think it would be better to outline an alternative to the current has part solution. https://www.wikidata.org/wiki/Wikidata:WikiProject_Mathematics#Properties_used_in_Wikipedia Physikerwelt (talk) 13:18, 8 December 2021 (UTC)

  Hello @Physikerwelt: With semantics are you referring to explaining variables appearing in a formula? This proposal here has a different purpose: Listing possible symbols that could be used to denote a mathematical entity; see the many provided examples. This is unrelated to the presence or absence of a formula. Toni 001 (talk) 09:51, 9 December 2021 (UTC)

•  Oppose just widen the scope of quantity symbol (LaTeX) (P7973). --Infovarius (talk) 20:24, 18 December 2021 (UTC)

  1. Quantity symbol is a well defined term in metrology (IEV), applicably to quantities, with very specific typesetting rules (ISO 80000-1:2009, 7 Printing rules).
  2. The property proposed here is intended for mathematical entities (excluding quantities), which have different typesetting rules (ISO 80000-2:2019, 4 Variables, functions and operators).

  In general we should strive for well-scoped properties, if possible; in this case the distinction is pretty clear. Toni 001 (talk) 08:42, 19 December 2021 (UTC)

  Just another comment to put this into the larger Wikidata context: We have element symbol (P246) for chemical elements, unit symbol (P5061) for units of measurement, ticker symbol (P249) for stocks. They may or may not have the same datatype, yet their independent existence is justified (I'm touching on the datatype here because one might be tempted to think that a fitting datatype alone justifies extending the scope of a property).

  Somewhat similarly, we use located in the present-day administrative territorial entity (P3842) instead of part of (P361) for geographic entities. Toni 001 (talk) 08:47, 20 December 2021 (UTC)

•  Not done - no consensus to create --DannyS712 (talk) 00:53, 2 January 2022 (UTC)