Date:

Wed, 28/12/201616:00-18:00

Location:

Ross 70

Better lucky than smart: realizing a quasi-generic class of measure preserving transformations as diffeomorphisms.

Speaker: Matthew Foreman

Abstract: In 1932, von Neumann proposed classifying measure preserving diffeomorphisms up to measure isomorphism. Joint work with B. Weiss

shows this is impossible in the sense that the corresponding equivalence relation is not Borel; hence impossible to capture using countable methods.

An accidental consequence of the proof addresses a different classical problem: which measure preserving transformations are isomorphic to diffeomorphisms of a compact smooth manifold?

In this talk we discuss the proof that a quasi-generic class of measure preserving transformations are isomorphic to measure preserving diffeomorphisms of the torus.

Speaker: Matthew Foreman

Abstract: In 1932, von Neumann proposed classifying measure preserving diffeomorphisms up to measure isomorphism. Joint work with B. Weiss

shows this is impossible in the sense that the corresponding equivalence relation is not Borel; hence impossible to capture using countable methods.

An accidental consequence of the proof addresses a different classical problem: which measure preserving transformations are isomorphic to diffeomorphisms of a compact smooth manifold?

In this talk we discuss the proof that a quasi-generic class of measure preserving transformations are isomorphic to measure preserving diffeomorphisms of the torus.