I have this proposition.
Let X,Y be a metric spaces and let $f:X \to Y$ be a map. Then f is continuous if and only if $f^{-1} (V)$ is closed in X whenever V is closed in Y.
How would you go about proving this?
I have this proposition.
Let X,Y be a metric spaces and let $f:X \to Y$ be a map. Then f is continuous if and only if $f^{-1} (V)$ is closed in X whenever V is closed in Y.
How would you go about proving this?