reserve A for QC-alphabet;
reserve i,j,k,l,m,n for Nat;
reserve a,b,e for set;
reserve t,u,v,w,z for QC-symbol of A;
reserve p,q,r,s for Element of CQC-WFF(A);
reserve x for Element of bound_QC-variables(A);
reserve ll for CQC-variable_list of k,A;
reserve P for QC-pred_symbol of k,A;
reserve f,h for Element of Funcs(bound_QC-variables(A),bound_QC-variables(A)),
  K,L for Element of Fin bound_QC-variables(A);

theorem Th43:
  [q,t,K,f] in SepQuadruples p implies not x.t in f.:(still_not-bound_in
  q)
proof
  assume
A1: [q,t,K,f] in SepQuadruples p;
  assume x.t in f.:(still_not-bound_in q);
  then t < t & t <= t by A1,Th42,QC_LANG1:22;
  hence contradiction by QC_LANG1:25;
end;
