- #1

- 986

- 9

## Homework Statement

As the title says

## Homework Equations

Definitions of "open" and "closed"

## The Attempt at a Solution

Suppose a finite set S is not closed. Then S

^{c}is not open, and there exists an element x of S

^{c}, so that for all µ > 0, either x + u, or x - u, is an element of S.

Hmmm ... Where do I go from here? I need a springboard.