renamed 'single' to 'some_rule'; added 'intro', 'elim';
renamed 'single' to 'some_rule';
added 'intro', 'elim';

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