FUNCTION: Ish - test whether the argument is a generator of the h-basis

CALLING SEQUENCE:

Ish(expr)

TYP[Ish](expr)

PARAMETERS:

expr = any expression

SYNOPSIS:

• The Ish function tests whether the argument expr is a generator of the h-basis.

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

EXAMPLES:

> with(TYP):
> Ish(h0);
 
                                     true
 
> Ish(h12);
 
                                     true