NOT function
Description
The function NOT(x) reverses the value of its boolean argument x. If x is 0 or FALSE then NOT(x) returns 1 (= TRUE). If x is 1 or TRUE then NOT(x) returns 0 (= FALSE).
The argument x can be a real number or a matrix. When it is a matrix, the function returns a matrix with the same dimensions and with the NOT function applied to all elements.
Example
NOT(5=5) returns FALSE.