anchor.diff:  //   ("=", A->A->bool)]
   axioms();;                                                                          // the_axioms database doesn't change
   definitions();;                                                                     // the_definitions doesn't change
  +!the_implicit_types;;                                                               // no change
  +type_abbrevs();;                                                                    // no change
   
   // after population of constants this parses
   parse_term @"~(p /\ q) <=> ~p \/ ~q";;
  
positive.code: //   ("\/", bool->bool->bool); ("?", (A->bool)->bool); ("!", (A->bool)->bool);
  //   ("==>", bool->bool->bool); ("/\", bool->bool->bool); ("T", bool);
  //   ("=", A->A->bool)]
  axioms();;                                                                          // no new axioms
  //  [|- !P x. P x ==> P ((@) P); |- !t. (\x. t x) = t]
  definitions();;                                                                     // lots of new definitions
  //  [|- PASSOC =
  //   (\_1099 _1100. _1099 ((FST _1100,FST (SND _1100)),SND (SND _1100)));
  
negative.code: 
  //* ind_defs Module *//
  EXISTS_EQUATION;; // forces ind_defs module evaluation
  !the_implicit_types;;                                                               // no change
  type_abbrevs();;                                                                    // no change
  // No Changes in internal databases status: to be checked better
  
  // Class Module *//
  