[014]The empty set \(\emptyset \) is a set. The formula for this axiom is
\[ β X : β Y Β¬(Y β X) \]
and by the preceding axiom, \(X\) is unique, so it is denoted by \(\emptyset \).
[014]The empty set \(\emptyset \) is a set. The formula for this axiom is
and by the preceding axiom, \(X\) is unique, so it is denoted by \(\emptyset \).