theorem Th58:
  |.0q.| = 0
proof
A1: Rea 0q = 0 by Lm6,Th16;
A2: Im1 0q = 0 by Lm6,Th16;
  Im2 0q = 0 by Lm6,Th16;
  hence thesis by A1,A2,Lm6,Th16,SQUARE_1:17;
end;
