theorem Th24:
  Rea <j> = 0 & Im1 <j> = 0 & Im2 <j> = 1 & Im3 <j> = 0 &
  Rea <k> = 0 & Im1 <k> = 0 & Im2 <k> = 0 & Im3 <k> = 1
 by Th16;
