MINUS _ _ _ _ _ _ _ _ _ _ _ _ operator
The minus operator is a unary minus, returning the negative of its argument. It is equivalent to the unary -.
minus(<expression>)
<expression> may be any scalar REDUCE expression.
minus(a); - A minus(-1); 1 minus((x+1)**4); 4 3 2 - (X + 4*X + 6*X + 4*X + 1)