- #1

- 986

- 9

## Homework Statement

Let

*A*be a nonempty set of real numbers which is bounded below. Let

*-A*be the set of all real numbers

*-x*, where

*x*is in

*A*. Prove that

*inf A = -sup(-A)*.

## Homework Equations

Definitions of upper bound, lower bound, least upper bound, and least lower bound.

## The Attempt at a Solution

Here's what I have so far:

Almost there! I just need to derive a contradiction on my assumption that gamma is an upper bound for

*-A*.