Epsilon tends to zero is wrong argument. In proofs, initially epsilon is considered as a small positive real number, later it is allowed to tend to zero.Now epsilon becomes non real.So epsilon fails to keep assumption on it as real. Can any maths professors clarify this? I asked this question in other form, the proof of the statement smallest positive real number doesn't exist is wrong. Since these arguments have been teaching in Under graduate and post graduate classes, Can any one bring a better proof?