section_path: Special sets of numbers in mathematics
section_name: Special sets of numbers in mathematics
paragraph_text: Special sets of numbers in mathematics
  
  There are sets of such mathematical importance, to which mathematicians refer so frequently, that they have acquired special names and notational conventions to identify them.
  
  Many of these important sets are represented in mathematical texts using bold (e.g. Z {\displaystyle \mathbf {Z} }) or blackboard bold (e.g. Z {\displaystyle \mathbb {Z} }) typeface. These include
  
  Each of the above sets of numbers has an infinite number of elements. Each is a subset of the sets listed below it.
  
  Sets of positive or negative numbers are sometimes denoted by superscript plus and minus signs, respectively. For example, Q + {\displaystyle \mathbf {Q} ^{+}} represents the set of positive rational numbers.