EntityQ1477744· pop 11· linked from 18 articlesunordered pairSign in to saveset having two elements a and b with no particular relation between themWikidata factsFollowssingletonShow 3 more factsP28202P6104WikiProject MathematicsP828axiom of pairingvia Wikidata · CC0ConnectionsmathematicsEntityInternational Standard Book NumberEntityCategoriesBasic concepts in set theory