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Re: Homeogeneous Spaces

Re: Homeogeneous Spaces  
Valeriu Anisiu
 Re: Homeogeneous Spaces  
Ron Sperber
From:Valeriu Anisiu
Subject:Re: Homeogeneous Spaces
Date:Sun, 23 Jan 2005 23:53:12 +0000 (UTC)
On 23 Jan 2005, William Elliot wrote:
>Topological space S is homogeneous when for all x,y in S,
> some auto-homeomorphism h:S -> S with h(x) = y.
>
>Is a connected subspace of homogeneous space homogeneous?
> No. [0,1] and [0,1) subset R are counterexamples.
>
>Is an open subspace of homogeneous space homogeneous?
>Is an open connected subspace of a homogeneous space homogeneous?
>
>Counter examples, of course, are welcome.
>
>----

No.
S=[0,1] with the natural topology is homogeneous,
[0,1) is open and connected _in S_ but it is not homogeneous.

V. Anisiu
From:Ron Sperber
Subject:Re: Homeogeneous Spaces
Date:Sun, 23 Jan 2005 22:58:26 -0500
Valeriu Anisiu wrote:
> On 23 Jan 2005, William Elliot wrote:
>
>>Topological space S is homogeneous when for all x,y in S,
>> some auto-homeomorphism h:S -> S with h(x) = y.
>>
>>Is a connected subspace of homogeneous space homogeneous?
>> No. [0,1] and [0,1) subset R are counterexamples.
>>
>>Is an open subspace of homogeneous space homogeneous?
>>Is an open connected subspace of a homogeneous space homogeneous?
>>
>>Counter examples, of course, are welcome.
>>
>>----
>
>
> No.
> S=[0,1] with the natural topology is homogeneous,
> [0,1) is open and connected _in S_ but it is not homogeneous.
>
> V. Anisiu
>
[0,1] is NOT homogeneous. There is no homeomorphism f:[0,1]->[0,1] with
f(0)=1/2 for example.
   

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