Mathematical Research Letters
Volume 20 (2013)
The isomorphism relation for separable $C*$-algebras
Pages: 1071 – 1080
We prove that the isomorphism relation for separable $C*$-algebras, the relations 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.