Wikidata:Property proposal/Crossing number

crossing number edit

Originally proposed at Wikidata:Property proposal/Natural science

Done: crossing number (P11035) (Talk and documentation)

Description	Crossing number for mathematical knots; the crossing number of a knot is the smallest number of crossings of any diagram of the knot. It is a knot invariant.
Represents	crossing number (Q2548661)
Data type	String
Domain	knot (Q1188853), link (Q1760728)
Allowed values	0\|[1-9][0-9]*
Example 1	unknot (Q1188344) → 0
Example 2	trefoil knot (Q168620) → 3
Example 3	figure-eight knot (Q168697) → 4
Example 4	Kinoshita–Terasaka knot (Q94827585) → 11
Source	https://knotinfo.math.indiana.edu/
Planned use	to add these values to entries for knots on Wikidata
Expected completeness	always incomplete (Q21873886)
See also	Dowker-Thistlethwaite notation (P8378)
Single-value constraint	yes
Wikidata project	WikiProject Mathematics (Q8487137)

Motivation edit

This is a mathematical invariant for knots. While this is available in external databases, it also belongs here on Wikidata. The Anome (talk) 12:27, 13 July 2022 (UTC)[reply]

Discussion edit

Notified participants of WikiProject Mathematics

Support ArthurPSmith (talk) 20:52, 13 July 2022 (UTC)[reply]
@The Anome: can you describe in more detail in the description what it means to be a "Crossing number"? ChristianKl ❪✉❫ 15:29, 19 July 2022 (UTC)[reply]
- @ChristianKl: Yes: see en:Crossing_number_(knot_theory) The Anome (talk) 18:34, 19 July 2022 (UTC)[reply]
  - @The Anome: I want more detail in the description, so that people who see the property on Wikidata have a better idea of what it's about. It doesn't help me at all to read the Wikipedia article for that purpose. ChristianKl ❪✉❫ 09:15, 20 July 2022 (UTC)[reply]
    - @ChristianKl: I've modified the description in the proposal above. I hope that's sufficient; if not, please let me know. The Anome (talk) 14:15, 20 July 2022 (UTC)[reply]
      Great. Support ChristianKl ❪✉❫ 20:53, 20 July 2022 (UTC)[reply]

Update: I've added a domain restriction, to just mathematical knots and links (and knots are of course a subset of links, but I thought I'd be explicit). Rationale: there is another concept of crossing number, en:Crossing number (graph theory), for graphs, but I think it's sufficiently different that we might want to make this a separate property. The Anome (talk) 10:27, 22 July 2022 (UTC)[reply]

@The Anome, ArthurPSmith, ChristianKl: Done --Tinker Bell ★ ♥ 01:14, 4 September 2022 (UTC)[reply]
Fabulous. I will generate the appropriate data tables and submit them to QuickStatements. The Anome (talk) 14:29, 7 September 2022 (UTC)[reply]