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AxiomOfChoice
Nov2-09, 09:16 AM
Is it true that every open set contains a compact set?

g_edgar
Nov2-09, 09:26 AM
Well, the empty set is open. And yes, even the empty set contains a compact set.

HallsofIvy
Nov3-09, 05:47 AM
Showing that one open set contains a compact set does not prove what the OP wanted!

However, I can finish by showing the "easy" part: If A is not empty, then it contains, say, "a". The singleton set "a", since it is finite, is compact.

g_edgar
Nov3-09, 07:42 AM
My point was, that every open set contains the empty open set, which contains the empty compact set. So I was not really doing *one* open set after all.