theorem Th68:
  for p holds for v,w holds v|still_not-bound_in p = w|
  still_not-bound_in p implies (J,v |= p iff J,w |= p)
proof
  defpred P[Element of CQC-WFF(Al)] means for v,w holds v|still_not-bound_in
   $1 = w|still_not-bound_in $1 implies (J,v |= $1 iff J,w |= $1);
A1: for p,q,x,k for l being CQC-variable_list of k,Al for P being
QC-pred_symbol of k,Al holds P[VERUM(Al)] & P[P!l] & (P[p] implies P['not' p])
   & (P[p] & P[q] implies P[p '&' q]) & (P[p] implies P[All(x,p)])
   by Th60,Th61,Th62,Th67,VALUAT_1:32;
  thus for p holds P[p] from CQC_LANG:sch 1(A1);
end;
