Axiom of Union

Last updated Nov 1, 2022

# Axiom

Formally, $$\forall A \exists B \forall c (c \in B \Leftrightarrow \exists D (c \in D \wedge D \in A)).$$ In other words, for any Set $A$ there exists a Set $B$ so that $B$ contains all the elements of the elements of $A$. We denote $B := \bigcup\limits A$.