section_path: Notation
section_name: Notation
paragraph_text: Notation
  
  The set of all natural numbers is standardly denoted N or N. {\displaystyle \mathbb {N}.} Older texts have occasionally employed J as the symbol for this set.
  
  Since natural numbers may contain 0 or not, it may be important to know which version is referred to. This is often specified by the context, but may also be done by using a subscript or a superscript in the notation, such as:
  
  Alternatively, since the natural numbers naturally form a subset of the integers (often denoted Z {\displaystyle \mathbb {Z} }), they may be referred to as the positive, or the non-negative integers, respectively. To be unambiguous about whether 0 is included or not, sometimes a superscript " ∗ {\displaystyle *} " or "+" is added in the former case, and a subscript (or superscript) "0" is added in the latter case: