Timeline for essential norm versus invertibility
Current License: CC BY-SA 3.0
4 events
| when toggle format | what | by | license | comment | |
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| S Aug 25, 2017 at 20:08 | history | suggested | LSpice | CC BY-SA 3.0 |
\parallel\parallel -> \lVert\rVert
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| Aug 25, 2017 at 20:05 | review | Suggested edits | |||
| S Aug 25, 2017 at 20:08 | |||||
| Aug 25, 2017 at 19:59 | comment | added | Bill Johnson | It is certainly not true in general. For example, write $X$ as the direct sum of an infinite dimensional closed subspace $Y$ and a one dimensional subspace $Z$ and consider an operator that is the identity on $Y$ and a small positive multiple of the identity on $Z$, so that in the Calkin algebra the operator is the identity element. | |
| Aug 25, 2017 at 19:39 | history | asked | Uğur Gül | CC BY-SA 3.0 |