and Subbases (cont.)
|
| Since the second axiom of countability has been mentioned, it seems only
| proper that the first be stated.  This axiom concerns a localized form of
| the notion of a base.  A 'base for the neighborhood system' of a point x,
| or a 'local base' at x, is a family of neighborhoods of x such that every
| neighborhood of x contains a member of the family.  For example, the family
| of open neighborhoods of a point is always a base for the neighborhood system.
| A topological space satis