tracial states on a finite dimensional $C^*$algebra

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If $A$ is a finite dimensional $C^*$ algebra,how many tracial states on $A$ ,is it countable or uncountable?How to construct a tracial state on $A$? Can anyone give me some hints?Thanks.







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    If $A$ is a finite dimensional $C^*$ algebra,how many tracial states on $A$ ,is it countable or uncountable?How to construct a tracial state on $A$? Can anyone give me some hints?Thanks.







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      If $A$ is a finite dimensional $C^*$ algebra,how many tracial states on $A$ ,is it countable or uncountable?How to construct a tracial state on $A$? Can anyone give me some hints?Thanks.







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      If $A$ is a finite dimensional $C^*$ algebra,how many tracial states on $A$ ,is it countable or uncountable?How to construct a tracial state on $A$? Can anyone give me some hints?Thanks.









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      asked Jul 21 at 18:04









      mathrookie

      437211




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          A finite-dimensional C$^*$-algebra is of the form
          $$
          A=bigoplus_j=1^m M_k_j(mathbb C).
          $$
          The number of states is indeed uncountable. Traces are precisely "convex combinations" of the traces in each block. That is, any trace on $A$ is of the form
          $$
          phi(bigoplus_j=1^m x_j)=sum_j=1^m t_j, tau_k_j(x_j),
          $$
          where $tau_k_j$ is the tracial state on $M_k_j(mathbb C)$ and $t_1,ldots, t_m$ are convex coefficients.






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            1 Answer
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            1 Answer
            1






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            up vote
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            accepted










            A finite-dimensional C$^*$-algebra is of the form
            $$
            A=bigoplus_j=1^m M_k_j(mathbb C).
            $$
            The number of states is indeed uncountable. Traces are precisely "convex combinations" of the traces in each block. That is, any trace on $A$ is of the form
            $$
            phi(bigoplus_j=1^m x_j)=sum_j=1^m t_j, tau_k_j(x_j),
            $$
            where $tau_k_j$ is the tracial state on $M_k_j(mathbb C)$ and $t_1,ldots, t_m$ are convex coefficients.






            share|cite|improve this answer

























              up vote
              1
              down vote



              accepted










              A finite-dimensional C$^*$-algebra is of the form
              $$
              A=bigoplus_j=1^m M_k_j(mathbb C).
              $$
              The number of states is indeed uncountable. Traces are precisely "convex combinations" of the traces in each block. That is, any trace on $A$ is of the form
              $$
              phi(bigoplus_j=1^m x_j)=sum_j=1^m t_j, tau_k_j(x_j),
              $$
              where $tau_k_j$ is the tracial state on $M_k_j(mathbb C)$ and $t_1,ldots, t_m$ are convex coefficients.






              share|cite|improve this answer























                up vote
                1
                down vote



                accepted







                up vote
                1
                down vote



                accepted






                A finite-dimensional C$^*$-algebra is of the form
                $$
                A=bigoplus_j=1^m M_k_j(mathbb C).
                $$
                The number of states is indeed uncountable. Traces are precisely "convex combinations" of the traces in each block. That is, any trace on $A$ is of the form
                $$
                phi(bigoplus_j=1^m x_j)=sum_j=1^m t_j, tau_k_j(x_j),
                $$
                where $tau_k_j$ is the tracial state on $M_k_j(mathbb C)$ and $t_1,ldots, t_m$ are convex coefficients.






                share|cite|improve this answer













                A finite-dimensional C$^*$-algebra is of the form
                $$
                A=bigoplus_j=1^m M_k_j(mathbb C).
                $$
                The number of states is indeed uncountable. Traces are precisely "convex combinations" of the traces in each block. That is, any trace on $A$ is of the form
                $$
                phi(bigoplus_j=1^m x_j)=sum_j=1^m t_j, tau_k_j(x_j),
                $$
                where $tau_k_j$ is the tracial state on $M_k_j(mathbb C)$ and $t_1,ldots, t_m$ are convex coefficients.







                share|cite|improve this answer













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                answered Jul 21 at 19:42









                Martin Argerami

                116k1071164




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