FUNCTION: IsBnPalin - test whether the argument is a palindromic permutation

CALLING SEQUENCE:

IsBnPalin(expr)

TYP[IsBnPalin](expr)

PARAMETERS:

expr = any expression

SYNOPSIS:

• The IsBnPalin function tests whether expr is a palindromic permutation of the symmetric group of degree 2*n, that is a permutation p for which 2*n+1-p[2*n+1-i] = p[i] for i=1..n, where n is nops(p)/2.

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

EXAMPLES:

> with(TYP):
> IsBnPalin([3, 2, 6, 1, 5, 4]);
 
                                     true