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 Th31:
  for q,t,K,f st ['not' q,t,K,f] in SepQuadruples p holds [q,t,K,f
  ] in SepQuadruples p
proof
  SepQuadruples(p) is_Sep-closed_on p by Def13;
  hence thesis;
end;
