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

theorem
  r => p in TAUT(A) & r => q in TAUT(A) implies r => ( p '&' q ) in TAUT(A)
proof
  assume that
A1: r => p in TAUT(A) and
A2: r => q in TAUT(A);
  ( r => p ) => (( r => q ) => ( r => ( p '&' q ))) in TAUT(A) by Th33;
  then ( r => q ) => ( r => ( p '&' q )) in TAUT(A) by A1,CQC_THE1:46;
  hence thesis by A2,CQC_THE1:46;
end;
