partially ordered set
Noun
Meaning
(set theory, order theory, loosely) A set that has a given, elsewhere specified partial order.
(set theory, order theory, formally) The ordered pair comprising a set and its partial order.
Source: en.wiktionary.orgSynonyms
Examples
An abstract polyhedron is a certain kind of partially ordered set (poset) of elements, such that adjacencies, or connections, between elements of the set correspond to adjacencies between elements (faces, edges, etc.) of a polyhedron.
Definition A partially ordered set (poset) P is said to satisfy the ascending chain condition (ACC) if every strictly ascending sequence of elements eventually terminates.
Empty chain as boundary case In the formulation of Zorn's lemma above, the partially ordered set P is not explicitly required to be non-empty.
Examples * The cofinality of a partially ordered set with greatest element is 1 as the set consisting only of the greatest element is cofinal (and must be contained in every other cofinal subset).
For instance, a lattice is a partially ordered set in which all finite subsets have both a supremum and an infimum, and a complete lattice is a partially ordered set in which all subsets have both a supremum and an infimum.
In mathematics, a complete lattice is a partially ordered set in which all subsets have both a supremum (join) and an infimum (meet).