I am told that the interval (a, ∞) where a [itex]\in[/itex] (0, ∞) together the empty set and [0, ∞) form a topology on [0, ∞).(adsbygoogle = window.adsbygoogle || []).push({});

But I thought in a topology that the intersection if any two sets had to also be in the topology, but the intersection of say (a, ∞) with (b, ∞) where a<b is surely (a,b) which isn't in the topology?

Help! Thanks!

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# Does this form a topology?

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