datatype thmref: added Fact; renamed Goal constant to prop;
datatype thmref: added Fact;
renamed Goal constant to prop;

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