reserve a,b,c,d for Real;
reserve z,z1,z2 for Complex;

theorem Th7:
  Re(<i>) = 0 & Im(<i>) = 1
proof
  reconsider zz=0,j=1 as Element of REAL by XREAL_0:def 1;
  <i> = [*zz,j*] by ARYTM_0:def 5,XCMPLX_0:def 1;
  hence thesis by Lm2;
end;
