20.  Glossary

partially ordered set; espace partiellement ordonné

Set with an order relation for which not all elements are comparable.

Filter ; filter

Stack of subsets of a given set stable at finite intersections.

Stack ; stack

Collection of subsets of a given set containing all the supersets of each of its members.

Order relation; order relation

Reflexive, anti-symmetrical and transitive relationship.

Trellis; lattice

Partially ordered space in which each pair of elements has an upper and a lower bound.