theorem Th22:
  t <= t
proof
  set R = the Relation of A;
  R well_orders QC-symbols(A) \ NAT by Def32;
  then
A1: R is_reflexive_in QC-symbols(A) \ NAT by WELLORD1:def 5;
  per cases;
  suppose t in NAT;
    hence thesis by Def33;
  end;
  suppose
A2: not t in NAT;
    then t in QC-symbols(A) \ NAT by XBOOLE_0:def 5;
    then [t,t] in the Relation of A by A1,RELAT_2:def 1;
    hence thesis by A2,Def33;
  end;
end;
