Talk:Q199
Autodescription — 1 (Q199)
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Instance of numeral (Q63116)?
[edit]Instance of numeral (Q63116) seems to me to be wrong. I would rather remove it. Instance of numeral (Q63116) are lexemes IMO. — Finn Årup Nielsen (fnielsen) (talk) 07:23, 29 May 2019 (UTC)
Unit
[edit]Hi. I boldly went ahead and created statements "instance of coherent SI unit" and "unit symbol 1", because that's what the SI Brochure (9th edition) (Q68977219) states: "unit one, symbol 1" and that a coherent SI unit is a product of powers of base units, without prefixes (except for kg). I'm leaving this message here because this must be a popular item. Toni 001 (talk) 18:43, 2 October 2019 (UTC)
@Jura1, Lucas Werkmeister (WMDE): Over three years ago the claim 1 (Q199)conversion to SI unit (P2370)1 (one) was created but then reverted by the author (pinging one developer because of the comment on top of this page). I would argue that the statement is both correct and useful:
- Correctness (summary of statements from the SI Brochure (9th edition) (Q68977219)): One is indeed a coherent SI unit (see explanation in section "Unit" above); it is a dimensionless unit; prefixes are not allowed; the unit symbol 1 can be omitted; coherent means that when converted to any coherent unit (there might be multiple valid choices, like C vs. A s), the magnitude is unique.
- Usefulness: When querying one might want to order the result by the value of some property. The form of the query for the value by which to sort depends on the datatype: If the datatype is not
wikibase:Quantitythen in many cases (strings, dates, ...)?x wdt:Pnnn ?orderValue .is sufficient, but in the case ofwikibase:Quantitya comparison makes only sense if all magnitudes are expressed in the same unit; this can be achieved by a property path?x p:Pnnn / psn:Pnnn / wikibase:quantityAmount ?orderValue .. However, thepsn:Pnnnpath element is not available if the statement's unit does not have a value for conversion to SI unit (P2370), which currently is the case for "dimensionless / one" (that is, 1 (Q199)). To handle this special case, the query is further complicated.
Therefore I propose to add (back) the statement 1 (Q199)conversion to SI unit (P2370)1 (one). Toni 001 (talk) 14:27, 3 October 2019 (UTC)
- In Wikidata, P2370 has also the function to define conversion among convertible units (most statements were copied into the query server configuration). There is a currently a gap for units like % or °/oo, but it's not strictly needed to also define it in Wikidata (there is a phab ticket for it). Personally, I don't mind if you re-add or not, but if we do, we should probably add it to percent (Q11229) as well. --- Jura 18:05, 3 October 2019 (UTC)
- Totally agree: percent, per mil, dozen, ..., should all have a conversion to SI unit (P2370) statement, stating how they relate to the unit "one" (I'll take care of that if there are no objections). Toni 001 (talk) 20:57, 3 October 2019 (UTC)
- I added the statement. Toni 001 (talk) 14:02, 5 October 2019 (UTC)
- Totally agree: percent, per mil, dozen, ..., should all have a conversion to SI unit (P2370) statement, stating how they relate to the unit "one" (I'll take care of that if there are no objections). Toni 001 (talk) 20:57, 3 October 2019 (UTC)