Timeline for Which sets occur as boundaries of other sets in topological spaces?
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
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| Jul 13, 2014 at 17:48 | comment | added | N Unnikrishnan | Sure, that was my confusion regarding relativisation. I have added notation for clarification. | |
| S Jul 13, 2014 at 17:48 | history | suggested | N Unnikrishnan | CC BY-SA 3.0 |
Added minor details, and notation
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| Jul 13, 2014 at 17:46 | review | Suggested edits | |||
| S Jul 13, 2014 at 17:48 | |||||
| Jul 11, 2014 at 16:19 | comment | added | Will Sawin | The point is not that the interior is usually dense, but that the interior union the complement is always dense. This is clear from the definition - consider an open set contained in the boundary of the set. Then it's contained in the set, and open, hence contained i the interior, hence not contained in the boundary. | |
| Jul 11, 2014 at 6:12 | comment | added | N Unnikrishnan | It seems the second last statement in the if part requires some clarification, in the case our set $A$ has isolated points, and hence its interior is not dense in it. I think adding those isolated points to the union will fix it. | |
| Jul 11, 2014 at 3:29 | history | answered | Will Sawin | CC BY-SA 3.0 |