FUNCTION: Rd2BnGa - calculate a product of generators

CALLING SEQUENCE:

Rd2BnGa(rd)

Rd2BnGa(rd, n)

BNA[Rd2BnGa](rd)

BNA[Rd2BnGa](rd, n)

PARAMETERS:

rd = any list denoting a decomposition

n = any positive integer

SYNOPSIS:

• The Rd2BnGa function calculates the product of the generators given by the decomposition rd which needs not to be reduced (0 denotes the special generator). The product is taken in the Bn-group algebra.

• Rd2BnGa(rd)=BN['BnRd2Code'](rd).

• When the second argument is not present, n is the smallest possible degree.

• Whenever there is a conflict between the function name Rd2BnGa and another name used in the same session, use the long form BNA['Rd2BnGa'].

EXAMPLES:

> with(BNA):
> Rd2BnGa([0,1,0,1], 5);
 
                                B[1, 3, 0, 0, 0]
 
> Rd2BnGa([0,1,0,1]);
 
                                     B[1, 3]