FUNCTION: IdcaMinus - difference of two elements of the idCoxeter algebra

CALLING SEQUENCE:

IdcaMinus(e_1, e_2)

IDCA[IdcaMinus](e_1, e_2)

PARAMETERS:

e_1, e_2 = any elements of the idCoxeter algebra

SYNOPSIS:

• The IdcaMinus function computes the difference between two elements of the idCoxeter algebra.

• One can use instead the operator &$-.

• Whenever there is a conflict between the function name IdcaMinus and another name used in the same session, use the long form IDCA['IdcaMinus'].

EXAMPLES:

> with(IDCA):
> a:=q + u/t*A[3,1,2]:
> b:=t - A[1,3,2]:
> IdcaMinus(a, b);
 
                                                  u A[3, 1, 2]
                A[1, 3, 2] + (q - t) A[1, 2, 3] + ------------
                                                        t
 
> a &$- a;
 
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