Dictionary of Arguments  
 
Empty set: an empty set is a set without an element. Notation ∅ or {}. There is only one empty set, since without an existing element there is no way to specify a specification of the set. The empty set can be specified as such that each element of the empty set is not identical with itself {x x unequal x}. Since there is no such object, the set must be empty. The empty set is not the number zero, but zero indicates the cardinality of the empty set. _____________ Annotation: The above characterizations of concepts are neither definitions nor exhausting presentations of problems related to them. Instead, they are intended to give a short introduction to the contributions below. – Lexicon of Arguments.  
Author  Item  More concepts for author  

Bigelow, John  Empty Set  Bigelow, John  
Frege, Gottlob  Empty Set  Frege, Gottlob  
Prior, Arthur  Empty Set  Prior, Arthur  
Quine, Willard Van Orman  Empty Set  Quine, Willard Van Orman  
Stechow, Arnim von  Empty Set  Stechow, Arnim von  
