Timeline for Counter example to lifting contractibility of a topological space
Current License: CC BY-SA 4.0
12 events
| when toggle format | what | by | license | comment | |
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| Jan 31, 2019 at 17:10 | comment | added | thibaud lemanissier | Thanks a lot for the link. I knew there were result like for compact CW-complex (using the result of "A Vietoris mapping theorem for homotopy" by S. Smale and the Whitehead theorem). But I didn't knew there was a result without the hypothesis of compactness. | |
| Jan 31, 2019 at 14:51 | comment | added | Moishe Kohan | Related: math.stackexchange.com/questions/3084432/… | |
| Jan 31, 2019 at 10:03 | comment | added | Yonatan Harpaz | @thibaudlemanissier, Right... my mistake. | |
| Jan 30, 2019 at 22:20 | comment | added | thibaud lemanissier | This map is not open because the image of $U=X\cap \{(x,y)\in[0,1]\times[-1,1] |\ |y|<1/2\}$ is an open set but $\varphi(U)$ is not a neighborhood of $0$ | |
| Jan 30, 2019 at 22:01 | comment | added | thibaud lemanissier | I may do a mistake but I think this map is not open | |
| Jan 30, 2019 at 21:55 | comment | added | Yonatan Harpaz | What about $X = \{(x,y) \in [0,1] \times [0,1] \;|\; x=0 \;\;\text{or}\;\; (x>0 \;\text{and}\; y=sin(1/x))\}$, $Y=[0,1]$ and $\varphi: X \to Y$ is the projection on the $x$-coordinate? All the conditions are clear except $\varphi$ being open, but I think it is open. | |
| Jan 30, 2019 at 16:56 | comment | added | thibaud lemanissier | It is a Berkovich space over Banach ring which is not valued field. I'm currently working on this space. | |
| Jan 30, 2019 at 16:45 | review | Close votes | |||
| Jan 31, 2019 at 8:45 | |||||
| Jan 30, 2019 at 16:33 | comment | added | wonderich | What are your examples? (say the complicated one) | |
| Jan 30, 2019 at 16:28 | history | edited | David White | CC BY-SA 4.0 |
Fixed typos while reading it, and now voting to close
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| Jan 30, 2019 at 16:25 | review | First posts | |||
| Jan 30, 2019 at 16:29 | |||||
| Jan 30, 2019 at 16:24 | history | asked | thibaud lemanissier | CC BY-SA 4.0 |