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On a question of Bratteli and Robinson

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We give a partial answer to a question raised by Bratteli and Robinson, by showing that the mean entropy equals the mean conditional entropy for a large class of translation invariant states. In the general case we show that equality holds if and only if the mean conditional entropy is upper semicontinuous in the w*-topology.

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Van Enter, A.C.D. On a question of Bratteli and Robinson. Lett Math Phys 6, 289–291 (1982). https://doi.org/10.1007/BF00400324

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  • Entropy
  • Statistical Physic
  • Group Theory
  • Large Class
  • Invariant State