3
$\begingroup$

I have a problem that puzzles me. I need to show that the two sets $A = \{(x,y) \in \mathbb{R}^2 \, \, \vert \, \, |x| \leq 1 \}$ and $B = \{(x,y) \in \mathbb{R}^2 \, \, \vert \, \, x \geq 0 \}$ are not homeomorphic; but I'm not able to figure out how start or what I need to arrive at.

4 Answers 4