# Difference between revisions of "Elementary interval"

of a partially ordered set

A subset consisting of two elements $a\leq b$ such that there are no other elements in the partially ordered set between them, i.e.

$$a\leq x\leq b\Rightarrow a=x\text{ or }a=b.$$

Elementary intervals are also called gaps or simple or atomic intervals.

For (elementary) intervals in $\mathbf R$ see Interval and segment; Interval, closed; Interval, open.

One says that in this situation, $b$ is a covering element of, or covers $a$.

How to Cite This Entry:
Elementary interval. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Elementary_interval&oldid=11924
This article was adapted from an original article by O.A. Ivanova (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article