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 Th12:
  'not' VERUM(A) => p in TAUT(A)
proof
  VERUM(A) => ('not' VERUM(A) => p) in TAUT(A) by CQC_THE1:43;
  hence thesis by CQC_THE1:41,46;
end;
