Possible Duplicate:
Are there sets in the K-Topology that aren’t open in the standard topology?
Of course this sounds like some materials from Munkre's book, but I still do not get why K-topology (collection of sets of the form $\{(a,b) \setminus K=\{\frac{1}{n}| n \in \mathbb{N} \}\}$ is finer than the standard topology.
It is easy to show that the lower limit topology is finer than the standard topology, but I am stuck on the case for K-topology.