$X$ and $Y$ are metric spaces, $A\subseteq X$, $A$ is bounded. map $f:X\to Y$ is continuous.
Questions:
- Is $A$ necessarily compact?
- Is $f(A)$ uniformly continuous?
- If given that $f$ is a bijection and $f(A)$ is compact, is $f^{-1}$ necessarily continuous?
Tried: If $A$ is closed and bounded, then $A$ must be compact hence compactness of $f(A)$ follows. So the question reduces to "is boundedness of $A$ sufficient for compactness?" Also, I think 3 is correct because bijection and compact domain and codomain should be enough for homeomorphism...
I am new to topology so really appreciate any help!
For 1,2 no. Consider $f(x)=\frac{1}{x}$ on $(0,1]$
For 3, no. Consider identity map from $[0,1]$ to $[0,1]$ , where the first one with discrete metric and the second one with standard metric.