nLab
cofinite subset

Contents

There are two notions: cofinite subset of a set and a cofinite subset of a (pre)ordered set.

Definition

Given a set XX, then a subset SXS \subset X is called cofinite if the complement X\SX \backslash S is a finite set.

A preordered set (Λ,)(\Lambda,\leq) is cofinite or closure finite if for every λΛ\lambda\in\Lambda the set of all predecessors of λ\lambda is finite.

Last revised on May 21, 2017 at 16:49:46. See the history of this page for a list of all contributions to it.