reserve Al for QC-alphabet;
reserve p,q,p1,p2,q1 for Element of CQC-WFF(Al),
  k for Element of NAT,
  f,f1,f2,g for FinSequence of CQC-WFF(Al),
  a,b,b1,b2,c,i,n for Nat;

theorem Th15:
  dom((g^f)|seq(len g,len f)) = seq(len g,len f)
proof
  dom((g^f)|seq(len g,len f)) = dom (g^f) /\ seq(len g,len f) by RELAT_1:61;
  hence thesis by Th14,XBOOLE_1:28;
end;
