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Homogenous spaces #787
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Making a PR for all the immediate results now. |
I believe every point belongs to infinitely-many open sets |
Oh, but we can argue about closed sets instead: |
Ah yes sorry. I got confused with S44. Yeah, closed sets will do the job. |
I feel like S44 would be better described as a product of the left ray topology on |
https://topology.pi-base.org/spaces?q=%3Fhomogenous
Spaces which are homogeneous:
https://topology.pi-base.org/spaces/S000015 (obvious from definition)
https://topology.pi-base.org/spaces/S000017 (obvious from definition)
https://topology.pi-base.org/spaces/S000018 (product of homogeneous spaces)
https://topology.pi-base.org/spaces/S000019 (obvious from definition since R is)
https://topology.pi-base.org/spaces/S000032 (standard result, see e.g. Infinite-dimensional topology by van Mill)
https://topology.pi-base.org/spaces/S000042 (obvious from definition)
Spaces which aren't homogeneous:$(\omega_1, 0)$ $\infty$ )$[0, 1]$ isn't)$x$ belongs must be the same for each $x$ )$0$ belongs to every open set, but there are points which don't)$a = 3/2$ and $b = 5/2$ then there are $U, V$ with $a\in U, b\notin U, a\notin V, b\in V$ yet no such neighbourhoods for $a = 1/2$ and $b = 1/4$ )
https://topology.pi-base.org/spaces/S000038 (obviously not homogeneous because of the point $(0, 0)$)
https://topology.pi-base.org/spaces/S000039 (not first countable only at
https://topology.pi-base.org/spaces/S000040 (not first countable only at
https://topology.pi-base.org/spaces/S000041 (because
https://topology.pi-base.org/spaces/S000044 (the amount of open sets to which
https://topology.pi-base.org/spaces/S000045 (
https://topology.pi-base.org/spaces/S000046 (if
This is just some of the spaces, but there is a lot of them which are easy to decide but have no mention on pi-base. Someone should update this.
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