reserve z,z1,z2 for Complex;
reserve r,x1,x2 for Real;
reserve p0,p,p1,p2,p3,q for Point of TOP-REAL 2;

theorem Th7:
  cpx2euc(z1+z2)=cpx2euc(z1)+cpx2euc(z2)
proof
  cpx2euc(z1)+cpx2euc(z2) =|[Re z1 + Re z2, Im z1 + Im z2]| by EUCLID:56;
  hence thesis by Th6;
end;
