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
  X |- (p => q) => r implies X |- q => r
proof
  assume
A1: X |- (p => q) => r;
  X|- ((p => q) => r) => (q => r) by CQC_THE1:59;
  hence thesis by A1,CQC_THE1:55;
end;
