▾ Set of symbols
▾ Alphabet
▾ Deduction system
▾ Theory
▾ Zermelo-Fraenkel set theory
▾ Set
▾ Binary cartesian set product
▾ Binary relation
▾ Map
Empty map
Formulation 0
A D18: Map $(X \times Y, f)$ is an empty map if and only if \begin{equation} X = \emptyset \end{equation}
Subdefinitions
» D4474: Canonical empty map