section_path: Definition and notation/Roster notation
section_name: Roster notation
paragraph_text: Roster notation
  
  Roster or enumeration notation defines a set by listing its elements between curly brackets, separated by commas:
  
  This notation was introduced by Ernst Zermelo in 1908. In a set, all that matters is whether each element is in it or not, so the ordering of the elements in roster notation is irrelevant (in contrast, in a sequence, a tuple, or a permutation of a set, the ordering of the terms matters). For example, {2, 4, 6} and {4, 6, 4, 2} represent the same set.
  
  For sets with many elements, especially those following an implicit pattern, the list of members can be abbreviated using an ellipsis '... '. For instance, the set of the first thousand positive integers may be specified in roster notation as