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May 31, 2018 at 15:29 comment added Student @NikWeaver You misunderstand me. I look at you references but i don't find what i look for.
May 31, 2018 at 15:02 comment added Nik Weaver @Student: I told you where to look. I understand you want me to do the work for you, but I'm not going to.
May 31, 2018 at 12:39 comment added Student @NikWeaver In all references which I find $H$ is assumed to be separable. I hope that if you find a reference which contains the proof in a general cae ( $H$ is not separable) the tell me in order to cite it. Thank you very much for your help.
May 29, 2018 at 23:56 comment added Nik Weaver @Student: I would just say "it is standard". The argument I gave is very standard stuff.
May 29, 2018 at 21:58 comment added Student @NikWeaver thank you. I can say in my paper that the measure can be taken semifinite without citing a reference?
May 29, 2018 at 21:42 comment added Nik Weaver @Student: I would just say "it is standard". If you really want a reference, you're going to have to go to the library and search through some books until you find it. Could be in Dunford & Schwarz, or in Reed & Simon, or Kadison-Ringrose, or Takesaki.
May 29, 2018 at 19:34 comment added Student @NikWeaver Could you please give me a reference to cite it in a paper? In the paper the Hilbert space is not necessarely separable. I want to use the spectral theorem and I want to say that the measure $\mu$ can be taken semifinite but I don't find any references to cite it. Thanks a lot for your help.
Mar 9, 2018 at 17:03 comment added David C. Ullrich @NateEldredge I was about to say that - didn't want to be pedantic...
Mar 9, 2018 at 16:08 comment added Nate Eldredge To be pedantic, I guess we should say that $\mu$ can be taken localizable. There is not a unique $\mu$ satisfying the theorem, and there will certainly exist such $\mu$ that are not semifinite.
Mar 8, 2018 at 20:50 comment added Nik Weaver No, for example counting measure on any set is localizable. It is a generalization of $\sigma$-finiteness to the nonseparable setting. Here is a little primer on localizablility for you (from a book of mine which is in press).
Mar 8, 2018 at 20:16 comment added Student Thank you. I think that a localizable measure is not in general $\sigma$-finite. Do you agree with me?
Mar 8, 2018 at 19:45 vote accept Student
Mar 8, 2018 at 16:16 comment added Nik Weaver Well, these are exercises. $E_0$ is the smallest subspace which is closed in norm and closed under application of $A_1$, $A_1^*$, $A_2$, and $A_2^*$.
Mar 8, 2018 at 15:59 comment added Student Thank you for your answer but I don't understand why $A_1E_0 \subseteq E_0$ and $A_1E_0^\perp \subseteq E_0^\perp$?
Mar 7, 2018 at 15:35 history answered Nik Weaver CC BY-SA 3.0