- #1
redbowlover
- 16
- 0
My quick question is this: I know it's true that any sequence in a compact metric space has a convergent subsequence (ie metric spaces are sequentially compact). Also, any arbitrary compact topological space is limit point compact, ie every (infinite) sequence has a limit point.
So in general, are the compact spaces that are not sequentially compact?
This is part of a larger problem: If a real-valued function on a topological space X is proper, show the image of f is closed. My idea was to chose a limit point y of f(X) and a sequence f(x_n) in f(X) converging to Y. Cover this sequence by a closed interval I. The the preimage of I is compact and contains the sequence x_n. Now, x_n has a limit point, say x.
If I could show f(x)=y, I'd be done. But i get stuck without being able to use sequential compactness.
THanks ahead of time
So in general, are the compact spaces that are not sequentially compact?
This is part of a larger problem: If a real-valued function on a topological space X is proper, show the image of f is closed. My idea was to chose a limit point y of f(X) and a sequence f(x_n) in f(X) converging to Y. Cover this sequence by a closed interval I. The the preimage of I is compact and contains the sequence x_n. Now, x_n has a limit point, say x.
If I could show f(x)=y, I'd be done. But i get stuck without being able to use sequential compactness.
THanks ahead of time