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 Mathematica with a text-based 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. »
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