There might be a bug in Axiom.   
      
   To get things right, you should use "factors factor y" instead   
   of "factors y".  You have to factor it first.   
      
   This version satisfies your requirements:   
      
   h(y:POLY INT):Boolean==   
    c := factors factor y   
    q := #c   
    output [q,c]   
    q=1 and c.1.exponent<2 => true   
    q=2 and ground?(c.1.factor) => true   
    false   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)