theorem Th1:
  p => (q => r) is valid implies (p '&' q) => r is valid
proof
A1: (p => (q => r)) => ((p '&' q) => r) in TAUT(A) by PROCAL_1:32;
  assume p => (q => r) in TAUT(A);
  hence (p '&' q) => r in TAUT(A) by A1,CQC_THE1:46;
end;
