reserve A for QC-alphabet;
reserve p, q, r, s, t for Element of CQC-WFF(A);
reserve X for Subset of CQC-WFF(A);

theorem Th9:
  (q => r) => ((p => q) => (p => r)) in TAUT(A)
proof
  (p => q) => ((q => r) => (p => r)) in TAUT(A) & ((p => q) => ((q => r) => (
  p => r))) => ((q => r) => ((p => q) => (p => r))) in TAUT(A) by Th1,Th8;
  hence thesis by CQC_THE1:46;
end;
