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

theorem Th36:
  (( p => r ) '&' ( q => r )) => (( p 'or' q ) => r) in TAUT(A)
proof
  set P = ( p => r );
  set Q = ( q => r );
  set R = (( p 'or' q ) => r);
  P => ( Q => R ) in TAUT(A) & (P => ( Q => R )) => (( P '&' Q ) => R ) in
  TAUT(A) by Th32,Th35;
  hence thesis by CQC_THE1:46;
end;
