fixes for equasions and equalities in MML >= 1172
    special articles not in mml.lar - changed in 1191; we omit hidden
    mml_added_spc([tarski]):- mml_version([_,_,X]), X < 1191,!.
    mml_added_spc([tarski_0, tarski_a]).
    fof_pred_def - will be needed for predicate expansion in the checker
 processing tarski_a and tarski_0