Timeline for Invertible operator with countable spectrum
Current License: CC BY-SA 3.0
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| Aug 19, 2014 at 17:12 | history | edited | Chandler | CC BY-SA 3.0 |
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| Aug 19, 2014 at 15:59 | history | edited | Chandler | CC BY-SA 3.0 |
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| Aug 19, 2014 at 15:48 | history | edited | Chandler | CC BY-SA 3.0 |
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| Aug 19, 2014 at 15:21 | comment | added | Christian Remling | On the other hand, it is easy to give an approximation directly if $A$ is self-adjoint: just approximate $\int_I t\, dE(t)$ by a suitable multiple of the identity on $E(I)$ for small intervals $I$, and put these pieces back together to obtain $B$. (This $B$ will have finite spectrum.) | |
| Aug 19, 2014 at 15:10 | comment | added | Christian Remling | The spectrum of $B$ is the closure of the eigenvalues, so this won't give countable spectrum. Quite on the contrary, you know that the essential spectrum is preserved. | |
| Aug 19, 2014 at 11:44 | history | edited | Chandler | CC BY-SA 3.0 |
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| Aug 19, 2014 at 10:28 | review | First posts | |||
| Aug 19, 2014 at 10:32 | |||||
| Aug 19, 2014 at 9:53 | history | answered | Chandler | CC BY-SA 3.0 |