De Morgan's Laws (Set Theory)/Relative Complement/Family of Sets

From ProofWiki
Jump to navigation Jump to search

Theorem

Let $S$ be a set.

Let $\family {S_i}_{i \mathop \in I}$ be a family of subsets of $S$.


Then:

Complement of Intersection

$\ds \relcomp S {\bigcap_{i \mathop \in I} S_i} = \bigcup_{i \mathop \in I} \relcomp S {S_i}$


Complement of Union

$\ds \relcomp S {\bigcup_{i \mathop \in I} S_i} = \bigcap_{i \mathop \in I} \relcomp S {S_i}$


Source of Name

This entry was named for Augustus De Morgan.


Sources