Editing Finitary relation (section)

=== Nullary ===
{{Main article|Relation of degree zero}}
Nullary (0-ary) relations count only two members: the empty nullary relation, which never holds, and the universal nullary relation, which always holds. This is because there is only one 0-tuple, the empty tuple (), and there are exactly two subsets of the (singleton) set of all 0-tuples. They are sometimes useful for constructing the base case of an [[Mathematical induction|induction]] argument.