Definition:Nest

Definition
Let $S$ be a set.

Let $\powerset S$ be its power set.

Let $N \subseteq \powerset S$ be a subset of $\powerset S$.

Then $N$ is a nest :


 * $\forall X, Y \in N: X \subseteq Y$ or $Y \subseteq X$

Also see

 * Definition:Chain (Set Theory)


 * Nest under Subset Ordering is Chain