FUNCTION: IsBnCode - test whether the argument is a code

CALLING SEQUENCE:

IsBnCode(expr)

TYP[IsBnCode](expr)

PARAMETERS:

expr = any expression

SYNOPSIS:

• The IsBnCode function tests whether expr is a code in the sense of a Bn Coxeter group, that is a list of n non negative integers, lesser than [1, 3, 5, 7, ...].

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

EXAMPLES:

> with(TYP):
> IsBnCode([-2, 3, 4]);
 
                                    false
 
> IsBnCode([1, 0, 5]);
 
                                     true