ThmDex – An index of mathematical definitions, results, and conjectures.
Set of symbols
Alphabet
Deduction system
Theory
Zermelo-Fraenkel set theory
Set
Binary cartesian set product
Binary relation
Definition D857
Empty binary relation
Formulation 0
A D4: Binary relation $(X \times Y, R)$ is an empty binary relation if and only if \begin{equation} R = \emptyset \end{equation}
Subdefinitions
Empty map
Children
Canonical empty binary relation