Timeline for Blocking visibility with cylinders
Current License: CC BY-SA 3.0
10 events
| when toggle format | what | by | license | comment | |
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| May 10, 2011 at 16:46 | comment | added | Gerhard Paseman | For general interest, I think there are a sequence of two or three (concentric?) not too large octahedron on whose faces one can lay one or two, or possibly three cylinders per face, tilted at different angles, so that the center point cannot see the points at infinity. Gerhard "Let Me Speak a Picture" Paseman, 2011.05.10 | |
| May 10, 2011 at 16:21 | comment | added | Yaakov Baruch | CLARIFICATION: a finite forest suffices because the projection of any open cylinder on the surface of the unit sphere is open and the sphere is compact. | |
| May 10, 2011 at 14:13 | history | edited | Yaakov Baruch | CC BY-SA 3.0 |
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| May 10, 2011 at 13:28 | comment | added | Yaakov Baruch | @Mark: you are right - I need to move the 4 islands of the forest a bit further away from the x-axis - I'm editing my answer accordingly. | |
| May 10, 2011 at 13:28 | history | edited | Yaakov Baruch | CC BY-SA 3.0 |
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| May 10, 2011 at 13:14 | comment | added | Mark Grant | @Yaakov: I'm afraid I don't follow. The cylinders parallel to $x$ seem to intersect with the trees in your forest with centres at $(x,\pm 1)$? | |
| May 10, 2011 at 13:11 | comment | added | Yaakov Baruch | I realize now, I simply added a forest of green cylinders to the last picture. | |
| May 10, 2011 at 13:07 | comment | added | Yaakov Baruch | I think this construction is very close to what Gerhard meant with his second comment to the question. | |
| May 10, 2011 at 13:00 | history | edited | Yaakov Baruch | CC BY-SA 3.0 |
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| May 10, 2011 at 12:54 | history | answered | Yaakov Baruch | CC BY-SA 3.0 |