A computability-theoretic reformulation of the Connes Embedding Problem
Abstract
The Connes Embedding Problem (CEP) asks whether every separable II_1 factor
embeds into an ultrapower of the hyperfinite II_1 factor. We show that the CEP
is equivalent to the computability of the universal theory of every type II_1
von Neumann algebra. We also derive some further computability-theoretic
consequences of the CEP.