Category:Domain of Union of Nest of Mappings is Union of Class of Domains

This category contains pages concerning Domain of Union of Nest of Mappings is Union of Class of Domains:

Let $N$ be a nest of mappings.

Let $\bigcup N$ denote the union of $N$.

Then:

$\Dom {\bigcup N} = \ds \bigcup_{f \mathop \in N} \Dom f$

where $\Dom f$ denotes the domain of $f$.