Bulletin of Symbolic Logic: Volume 15 - Issue 2

When are Two Algorithms the Same?
Andreas Blass, Nachum Dershowitz, Yuri Gurevich
Published online by Cambridge University Press:

15 January 2014, pp. 145-168
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People usually regard algorithms as more abstract than the programs that implement them. The natural way to formalize this idea is that algorithms are equivalence classes of programs with respect to a suitable equivalence relation. We argue that no such equivalence relation exists.

Borel Reductibility and Classification of von Neumann Algebras
Román Sasyk, Asger Törnquist
Published online by Cambridge University Press:

15 January 2014, pp. 169-183
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We announce some new results regarding the classification problem for separable von Neumann algebras. Our results are obtained by applying the notion of Borel reducibility and Hjorth's theory of turbulence to the isomorphism relation for separable von Neumann algebras.

Automatic Continuity of Group Homomorphisms
Christian Rosendal
Published online by Cambridge University Press:

15 January 2014, pp. 184-214
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We survey various aspects of the problem of automatic continuity of homomorphisms between Polish groups.

Bulletin of Symbolic Logic