# empty set (Q226183)

| Property ID | Property | Value | Value entity | Amount | Unit | Date / from | Until | Rank | Sources |
| --- | --- | --- | --- | ---: | --- | --- | --- | --- | --- |
| P31 | Instance of | set | Q36161 |  |  |  |  | normal |  |
| P31 | Instance of | open set | Q213363 |  |  |  |  | normal |  |
| P31 | Instance of | closed set | Q320357 |  |  |  |  | normal |  |
| P31 | Instance of | null set | Q1201815 |  |  |  |  | normal |  |
| P31 | Instance of | 0-ad | Q39604693 |  |  |  |  | normal |  |
| P31 | Instance of | finite set | Q272404 |  |  |  |  | normal |  |
| P2820 | Set cardinality | zero | Q204 |  |  |  |  | normal |  |
| P1889 | Different from | y | Q28827 |  |  |  |  | normal |  |
| P1889 | Different from | singleton of 0 | Q30027695 |  |  |  |  | normal |  |
| P1889 | Different from | null set | Q1201815 |  |  |  |  | normal |  |
| P1993 | TeX string | \empty |  |  |  |  |  | normal |  |
| P1993 | TeX string | \emptyset |  |  |  |  |  | normal |  |
| P1993 | TeX string | \varnothing |  |  |  |  |  | normal |  |
| P461 | Opposite of | non-empty set | Q10533491 |  |  |  |  | normal |  |
| P913 | Notation | ∅ | Q7068971 |  |  |  |  | normal |  |
| P361 | Part of | list of types of sets | Q28659876 |  |  |  |  | normal |  |
| P460 | Said to be the same as | 0-ad | Q39604693 |  |  |  |  | normal |  |
| P6771 | Arabic Ontology concept ID | 293242 |  |  |  |  |  | normal | https://ontology.birzeit.edu/concept/293242 |
| P7554 | Encyclopedia of Mathematics article ID | Empty_set |  |  |  |  |  | normal | https://encyclopediaofmath.org/wiki/Empty_set |
| P646 | Freebase ID | /m/02ly0 |  |  |  |  |  | normal | https://www.google.com/search?kgmid=/m/02ly0 |
| P227 | GND ID | 136192019X |  |  |  |  |  | normal | https://d-nb.info/gnd/136192019X |
| P11514 | Great Russian Encyclopedia portal ID | pustoe-mnozhestvo-aa612b |  |  |  |  |  | normal | https://bigenc.ru/c/pustoe-mnozhestvo-aa612b |
| P8313 | Lex ID | Ø_-_den_tomme_mængde |  |  |  |  |  | normal | https://wikidata-externalid-url.toolforge.org/?p=8313&url_prefix=https://lex.dk/&id=%C3%98_-_den_tomme_m%C3%A6ngde |
| P2812 | MathWorld ID | EmptySet |  |  |  |  |  | normal | https://mathworld.wolfram.com/EmptySet.html |
| P12888 | Metamath statement ID | df-nul |  |  |  |  |  | normal | https://us.metamath.org/mpeuni/df-nul.html |
| P6366 | Microsoft Academic ID (discontinued) | 93713127 |  |  |  |  |  | normal | https://web.archive.org/web/https://academic.microsoft.com/v2/detail/93713127 |
| P4215 | NLab ID | empty set |  |  |  |  |  | normal | https://ncatlab.org/nlab/show/empty%20set |
| P6781 | ProofWiki ID | Definition:Empty_Set |  |  |  |  |  | normal | https://proofwiki.org/wiki/Definition%3AEmpty_Set |
| P9621 | Treccani's Enciclopedia della Matematica ID | insieme-vuoto |  |  |  |  |  | normal | https://www.treccani.it/enciclopedia/insieme-vuoto_(Enciclopedia-della-Matematica) |
| P12800 | Vikidia article ID | fr:Ensemble_vide |  |  |  |  |  | normal | https://central.vikidia.org/wiki/fr%3AEnsemble_vide |

Source: https://aidb.si/e/empty-set-Q226183 — Wikidata (CC0) via AIDb