FUNCTION: BnRd2Code - calculate a code from a decomposition into simple reflections

CALLING SEQUENCE:

BnRd2Code(rd)

BnRd2Code(rd, n)

BN[BnRd2Code](rd)

BN[BnRd2Code](rd, n)

PARAMETERS:

rd = any list denoting a decomposition

n = any positive integer

SYNOPSIS:

• The BnRd2Code function computes the code corresponding to the list rd, considered as a product of simple reflections. The special generator is denoted 0.

• Let rd=[i,j,k,...], then BnRd2Code(rd)=SG[MultPerm](s_i, s_j, s_k, ...) where s_i stands for BnTranspoPalin(i).

• When the second argument is not present, n is taken to be the smallest possible one.

• The decomposition needs not to be reduced.

• Whenever there is a conflict between the function name BnRd2Code and another name used in the same session, use the long form BN['BnRd2Code'].

EXAMPLES:

> with(BN):
> BnRd2Code([0, 1, 2, 1, 0, 1, 2]);
 
                                   [1, 1, 5]