Space S000133
Real line with post office metric
Also known as: Real plane with post office metric
A space with a particular point satisfying:
- Each point is isolated.
- The point has a countable neighborhood base such that , and for each n, and .
These conditions uniquely determine the space up to homeomorphism, as shown in Math StackExchange 4833751.
Here are a few examples of spaces satisfying the conditions (see Math StackExchange 4834226).
-
The space with . The basic open neighborhoods of are the Euclidean open intervals around .
-
The post office metric space defined as counterexample #139 ("The Post Office Metric") in DOI 10.1007/978-1-4612-6290-9, where with and is the origin. The post office metric on is defined by:
- The ordered space with its order topology, where has its lexicographical ordering and is an additional maximum point (and the particular point).
Id | If | Then |
---|---|---|
T65 | Weakly locally compact ∧ Metrizable | Completely metrizable |
T269 | Weakly locally compact ∧ ∧ Totally disconnected | Zero dimensional |