clarified signature -- avoid oddities of Iterable like Iterator.map; specific toString;
clarified signature -- avoid oddities of Iterable like Iterator.map;
specific toString;

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle