Nitpicking: surjective functions do not relate to unicity of ouptuts; you'd rather talk about non-injective functions. I agree with your point, though. (surjec

Nitpicking: surjective functions do not relate to unicity of ouptuts; you'd rather talk about non-injective functions. I agree with your point, though. (surjective != non-injective, in the same way that non-increasing != decreasing)