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

theorem
  'not' ( p 'or' q ) => 'not' p in TAUT(A)
proof
  ( p => ( p 'or' q )) => ( 'not' ( p 'or' q ) => 'not' p ) in TAUT(A) & ( p
  => ( p 'or' q )) in TAUT(A) by Th3,LUKASI_1:26;
  hence thesis by CQC_THE1:46;
end;
