FUNCTION: HekaMinus - difference of two elements of the Hecke algebra

CALLING SEQUENCE:

HekaMinus(e_1, e_2)

HEKA[HekaMinus](e_1, e_2)

PARAMETERS:

e_1, e_2 = any elements of the Hecke algebra

SYNOPSIS:

• The HekaMinus function computes the difference between two elements of the Hecke algebra.

• One can use instead the operator &?-.

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

EXAMPLES:

> with(HEKA):
> a:=q + u/t*A[3,1,2]:
> b:=t - A[1,3,2]:
> HekaMinus(a, b);
 
                                                  u A[3, 1, 2]
                (q - t) A[1, 2, 3] + A[1, 3, 2] + ------------
                                                        t
 
> a &?- a;
 
                                       0