Timeline for A norm one projection
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
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| Apr 13, 2017 at 12:58 | history | edited | CommunityBot |
replaced http://mathoverflow.net/ with https://mathoverflow.net/
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| Dec 17, 2013 at 15:44 | vote | accept | Frege | ||
| Dec 16, 2013 at 19:01 | vote | accept | Frege | ||
| Dec 16, 2013 at 19:01 | |||||
| Dec 15, 2013 at 23:25 | comment | added | Narutaka OZAWA | If there is a norm one projection, then $\cal A$ has to be self-adjoint, because unital norm one maps are automatically positive. Every self-adoint maximal abelian subalgebra ${\cal A}\subset{\cal B}(H)$ is unitarily equivalent to $L^\infty(X,\mu)\subset{\cal B}(L^2(X,\mu))$. | |
| Dec 15, 2013 at 21:50 | comment | added | Alain Valette | In their famous 1959 paper where they introduce the Kadison-Singer problem (recently solved), R.V. Kadison and I.M. Singer prove that, in the case of $\ell^2$, taking the diagonal is the only projection onto the corresponding MASA of diagonal operators; and that for $L^2[0,1]$ there are at least two projections on the MASA $L^\infty [0,1]$; see jstor.org/discover/10.2307/… | |
| Dec 15, 2013 at 12:49 | history | answered | Tomasz Kania | CC BY-SA 3.0 |