minus

Minus operation for rtau object.


Syntax
   f = minus(obj1, obj2)

Description
    minus(obj1, obj2) returns the coefficient diference obj1 - obj2.

Inputs
   obj1 = minuend (ctau object).
   obj2 = subtrahend (rtau object).

Output
   F    = obj1.coef - obj2.coef (ctau object).