Well, if you just assume e^{i\pi} = -1 holds**, then you simply have e^{i\pi + 1} = -e. Since e^{x} = n is defined in \mathbb{R}^2 for any n > 0, you can come up with any z such that e^{i\pi + z} = - n for any positive n.** Of course, you don't have to assume anything. :biggrin: The proofs for...