- #1

robertdeniro

- 39

- 0

## Homework Statement

X and Y are two closed non-empty subsets of R (real numbers).

define X+Y to be (x+y | x belongs to X and y belongs to Y)

give an example where X+Y is not closed

## Homework Equations

## The Attempt at a Solution

i tried X=all integers and Y=[0 1] but that didnt work out.

i know X+Y must be non-finite because all finite subsets are closed.