removed obsolete is_fact (cf. Thm.no_prems);
removed obsolete is_fact (cf. Thm.no_prems);

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