The isomorphism relation for separable C*-algebras

@article{Elliott2013TheIR,
  title={The isomorphism relation for separable C*-algebras},
  author={George A. Elliott and Ilijas Farah and Vern I. Paulsen and Christian Rosendal and Andrew S. Toms and Asger Tornquist},
  journal={Mathematical Research Letters},
  year={2013},
  volume={20},
  pages={1071-1080}
}
We prove that the isomorphism relation for separable C ∗ -algebras, the rela- tions of complete and n-isometry for operator spaces, and the relations of unital n-order isomorphisms of operator systems, are Borel reducible to the orbit equivalence relation of a Polish group action on a standard Borel space. 
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