Talk:Neighbourhood system

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Mathematics rating:
Start Class
Mid Importance
 Field: Topology

The union of local bases for all points x are a base for the topology[edit]

I don't see this being true. A neighbourhood of x (in the neighbourhood basis \mathcal{B}(x) of x) may be closed - a base of the topology, however, only admits open subsets. Where does this come from? Quiet photon (talk) 08:39, 31 January 2011 (UTC)