Existence of faithful normal state

The name of the pictureThe name of the pictureThe name of the pictureClash Royale CLAN TAG#URR8PPP











up vote
1
down vote

favorite












Does there always exist faithful normal state on center of von Neumann algebra?



Further, in type II$_1$ von Neumann algebras are tracial states coming from the center valued trace?







share|cite|improve this question

























    up vote
    1
    down vote

    favorite












    Does there always exist faithful normal state on center of von Neumann algebra?



    Further, in type II$_1$ von Neumann algebras are tracial states coming from the center valued trace?







    share|cite|improve this question























      up vote
      1
      down vote

      favorite









      up vote
      1
      down vote

      favorite











      Does there always exist faithful normal state on center of von Neumann algebra?



      Further, in type II$_1$ von Neumann algebras are tracial states coming from the center valued trace?







      share|cite|improve this question













      Does there always exist faithful normal state on center of von Neumann algebra?



      Further, in type II$_1$ von Neumann algebras are tracial states coming from the center valued trace?









      share|cite|improve this question












      share|cite|improve this question




      share|cite|improve this question








      edited Jul 21 at 12:45









      Martin Argerami

      116k1071164




      116k1071164









      asked Jul 19 at 20:22









      mathlover

      10518




      10518




















          1 Answer
          1






          active

          oldest

          votes

















          up vote
          1
          down vote



          accepted










          The first question is the same as asking if every abelian von Neumann algebra has a faithful normal state. The answer is easily no, by taking for instance the example in this answer.



          As for all tracial states coming from the center-valued trace, it is not entirely clear to me what you mean. If you have
          $$
          M=bigoplus_n A_notimes N_n,
          $$
          where $A_n$ are abelian and $N_n$ are II$_1$-factors, the center-valued trace is induced by
          $$
          Phi(bigoplus_n a_notimes x_n)=bigoplus_n a_notimes 1.
          $$
          Tracial states are obtained by taking $f_nin S(A_n)$ and $tau_n$ the unique trace on $N_n$, and letting
          $$
          phi(bigoplus_n a_notimes x_n)=sum_n f_n(a_n)tau(x_n).
          $$
          I cannot immediately say in what sense $phi$ "comes" from $Phi$.






          share|cite|improve this answer





















          • Meaning is if $rho$ is a tracial state in von Neumann algebra(factor), does there exist centervalued trace $phi$ such that $phi(A)=rho(A)I$
            – mathlover
            Jul 21 at 18:31










          • The center-valued trace is unique.
            – Martin Argerami
            Jul 21 at 19:24










          Your Answer




          StackExchange.ifUsing("editor", function ()
          return StackExchange.using("mathjaxEditing", function ()
          StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix)
          StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
          );
          );
          , "mathjax-editing");

          StackExchange.ready(function()
          var channelOptions =
          tags: "".split(" "),
          id: "69"
          ;
          initTagRenderer("".split(" "), "".split(" "), channelOptions);

          StackExchange.using("externalEditor", function()
          // Have to fire editor after snippets, if snippets enabled
          if (StackExchange.settings.snippets.snippetsEnabled)
          StackExchange.using("snippets", function()
          createEditor();
          );

          else
          createEditor();

          );

          function createEditor()
          StackExchange.prepareEditor(
          heartbeatType: 'answer',
          convertImagesToLinks: true,
          noModals: false,
          showLowRepImageUploadWarning: true,
          reputationToPostImages: 10,
          bindNavPrevention: true,
          postfix: "",
          noCode: true, onDemand: true,
          discardSelector: ".discard-answer"
          ,immediatelyShowMarkdownHelp:true
          );



          );








           

          draft saved


          draft discarded


















          StackExchange.ready(
          function ()
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2857022%2fexistence-of-faithful-normal-state%23new-answer', 'question_page');

          );

          Post as a guest






























          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes








          up vote
          1
          down vote



          accepted










          The first question is the same as asking if every abelian von Neumann algebra has a faithful normal state. The answer is easily no, by taking for instance the example in this answer.



          As for all tracial states coming from the center-valued trace, it is not entirely clear to me what you mean. If you have
          $$
          M=bigoplus_n A_notimes N_n,
          $$
          where $A_n$ are abelian and $N_n$ are II$_1$-factors, the center-valued trace is induced by
          $$
          Phi(bigoplus_n a_notimes x_n)=bigoplus_n a_notimes 1.
          $$
          Tracial states are obtained by taking $f_nin S(A_n)$ and $tau_n$ the unique trace on $N_n$, and letting
          $$
          phi(bigoplus_n a_notimes x_n)=sum_n f_n(a_n)tau(x_n).
          $$
          I cannot immediately say in what sense $phi$ "comes" from $Phi$.






          share|cite|improve this answer





















          • Meaning is if $rho$ is a tracial state in von Neumann algebra(factor), does there exist centervalued trace $phi$ such that $phi(A)=rho(A)I$
            – mathlover
            Jul 21 at 18:31










          • The center-valued trace is unique.
            – Martin Argerami
            Jul 21 at 19:24














          up vote
          1
          down vote



          accepted










          The first question is the same as asking if every abelian von Neumann algebra has a faithful normal state. The answer is easily no, by taking for instance the example in this answer.



          As for all tracial states coming from the center-valued trace, it is not entirely clear to me what you mean. If you have
          $$
          M=bigoplus_n A_notimes N_n,
          $$
          where $A_n$ are abelian and $N_n$ are II$_1$-factors, the center-valued trace is induced by
          $$
          Phi(bigoplus_n a_notimes x_n)=bigoplus_n a_notimes 1.
          $$
          Tracial states are obtained by taking $f_nin S(A_n)$ and $tau_n$ the unique trace on $N_n$, and letting
          $$
          phi(bigoplus_n a_notimes x_n)=sum_n f_n(a_n)tau(x_n).
          $$
          I cannot immediately say in what sense $phi$ "comes" from $Phi$.






          share|cite|improve this answer





















          • Meaning is if $rho$ is a tracial state in von Neumann algebra(factor), does there exist centervalued trace $phi$ such that $phi(A)=rho(A)I$
            – mathlover
            Jul 21 at 18:31










          • The center-valued trace is unique.
            – Martin Argerami
            Jul 21 at 19:24












          up vote
          1
          down vote



          accepted







          up vote
          1
          down vote



          accepted






          The first question is the same as asking if every abelian von Neumann algebra has a faithful normal state. The answer is easily no, by taking for instance the example in this answer.



          As for all tracial states coming from the center-valued trace, it is not entirely clear to me what you mean. If you have
          $$
          M=bigoplus_n A_notimes N_n,
          $$
          where $A_n$ are abelian and $N_n$ are II$_1$-factors, the center-valued trace is induced by
          $$
          Phi(bigoplus_n a_notimes x_n)=bigoplus_n a_notimes 1.
          $$
          Tracial states are obtained by taking $f_nin S(A_n)$ and $tau_n$ the unique trace on $N_n$, and letting
          $$
          phi(bigoplus_n a_notimes x_n)=sum_n f_n(a_n)tau(x_n).
          $$
          I cannot immediately say in what sense $phi$ "comes" from $Phi$.






          share|cite|improve this answer













          The first question is the same as asking if every abelian von Neumann algebra has a faithful normal state. The answer is easily no, by taking for instance the example in this answer.



          As for all tracial states coming from the center-valued trace, it is not entirely clear to me what you mean. If you have
          $$
          M=bigoplus_n A_notimes N_n,
          $$
          where $A_n$ are abelian and $N_n$ are II$_1$-factors, the center-valued trace is induced by
          $$
          Phi(bigoplus_n a_notimes x_n)=bigoplus_n a_notimes 1.
          $$
          Tracial states are obtained by taking $f_nin S(A_n)$ and $tau_n$ the unique trace on $N_n$, and letting
          $$
          phi(bigoplus_n a_notimes x_n)=sum_n f_n(a_n)tau(x_n).
          $$
          I cannot immediately say in what sense $phi$ "comes" from $Phi$.







          share|cite|improve this answer













          share|cite|improve this answer



          share|cite|improve this answer











          answered Jul 21 at 12:44









          Martin Argerami

          116k1071164




          116k1071164











          • Meaning is if $rho$ is a tracial state in von Neumann algebra(factor), does there exist centervalued trace $phi$ such that $phi(A)=rho(A)I$
            – mathlover
            Jul 21 at 18:31










          • The center-valued trace is unique.
            – Martin Argerami
            Jul 21 at 19:24
















          • Meaning is if $rho$ is a tracial state in von Neumann algebra(factor), does there exist centervalued trace $phi$ such that $phi(A)=rho(A)I$
            – mathlover
            Jul 21 at 18:31










          • The center-valued trace is unique.
            – Martin Argerami
            Jul 21 at 19:24















          Meaning is if $rho$ is a tracial state in von Neumann algebra(factor), does there exist centervalued trace $phi$ such that $phi(A)=rho(A)I$
          – mathlover
          Jul 21 at 18:31




          Meaning is if $rho$ is a tracial state in von Neumann algebra(factor), does there exist centervalued trace $phi$ such that $phi(A)=rho(A)I$
          – mathlover
          Jul 21 at 18:31












          The center-valued trace is unique.
          – Martin Argerami
          Jul 21 at 19:24




          The center-valued trace is unique.
          – Martin Argerami
          Jul 21 at 19:24












           

          draft saved


          draft discarded


























           


          draft saved


          draft discarded














          StackExchange.ready(
          function ()
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2857022%2fexistence-of-faithful-normal-state%23new-answer', 'question_page');

          );

          Post as a guest













































































          Comments

          Popular posts from this blog

          What is the equation of a 3D cone with generalised tilt?

          Color the edges and diagonals of a regular polygon

          Relationship between determinant of matrix and determinant of adjoint?