Wolfram Language & System 10.4 (2016)|Legacy Documentation

This is documentation for an earlier version of the Wolfram Language.View current documentation (Version 11.2)


is the logical NOT function. It gives False if expr is True, and True if it is False.


  • Not[expr] can be input in StandardForm and InputForm as ¬expr. The character can be entered as Esc!Esc, EscnotEsc, or . »
  • Not gives symbolic results when necessary, applying various simplification rules to them.
  • If you are using the Wolfram System with a textbased front end, then you cannot use the notation !expr for Not[expr] if it appears at the very beginning of a line. In this case, !expr is interpreted as a shell escape. »
Introduced in 1988
| Updated in 1996