theorem
  F /// (G /\ H) c= (F///G) /\ (F///H)
proof
  (G /\ H)"" c= (G"")/\(H"") by Th24;
  then
A1: F**((G /\ H)"") c= F**((G"")/\(H"")) by Th81;
  F**((G"")/\(H"")) c= (F**(G""))/\(F**(H"")) by Th83;
  hence thesis by A1;
end;
