1. The problem statement, all variables and given/known data Let S be a non empty set that is bounded about and β = sup S. Prove that for each ε > 0 there exists a point x in S such that x > β - ε. 2. Relevant equations 3. The attempt at a solution I don't really know how to begin this. I know it's true; I'm looking at the problem and I'm like, "Well, duh," but I can't prove it. I know that x ≤ β, and that β - ε ≤ x. Is there more that I have to do? edit: never mind. I'm an idiot. Proof by contradiction makes this really easy.