- #1

Kernul

- 211

- 7

## Homework Statement

Verify that if an interval is bounded it must be one of the four following types: ##(a, b)##, ##[a, b]##, ##(a, b]##, or ##[a, b)##.

## Homework Equations

## The Attempt at a Solution

I don't quite get what I should actually prove here.

Do I have to see if, for ##A \subseteq S##, we have ##\forall x \in S, a < x < b##, with ##a## and ##b## being the lower and upper bound of ##A##? (this is for the first type ##(a, b)##)