FUNCTION: Rd2Sga - calculate a product of generators

CALLING SEQUENCE:

Rd2Sga(rd)

Rd2Sga(rd, n)

SGA[Rd2Sga](rd)

SGA[Rd2Sga](rd, n)

PARAMETERS:

rd = any list denoting a decomposition

n = any positive integer denoting the degree of a symmetric group

SYNOPSIS:

• The Rd2Sga function calculates the product of the generators given by the reduced decomposition rd. The product is taken in the symmetric group algebra.

• Rd2Sga(rd)=SG['Rd2Perm'](rd).

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

• Whenever there is a conflict between the function name Rd2Sga and another name used in the same session, use the long form SGA['Rd2Sga'].

EXAMPLES:

> with(SGA):
> Rd2Sga([1,2,1], 5);
 
                                 A[3, 2, 1, 4, 5]
 
> Rd2Sga([1,2,1]);
 
                                    A[3, 2, 1]
 
> Rd2Sga([1,2,1,2]);
 
                                    A[3, 1, 2]