Home›Browse›filter🌐EnglishEnglishDeutschEspañolFrançaisItalianoNederlandsPolskiPortuguêsРусский한국어中文日本語EntityQ1052692· pop 21· linked from 155 articlesfilterSign in to savein order theory, a nonempty, downward‐directed, upward‐closed subset of a preordered setAvailable in 21 languagesEspañolFrançaisDeutsch中文日本語РусскийPortuguêsItalianoCatalanCzechEstonianFinnishHebrewHungarianNederlandsPiedmontesePolskiSerbianShow 2 moreUkrainian한국어via Wikidata sitelinks · CC0