On rank and isomorphism of von Neumann special flows

Thursday, April 27, 2017 -
11:00am to 12:30pm
Please note special time and location.  A von Neumann flow is a special flow over an irrational rotation of the circle and under a piecewise smooth roof function with a non-zero sum of jumps. Such flows appear naturally as special representations of Hamiltonian flows on the torus with critical points. We consider the class of von Neumann flows with one discontinuity. I will show that any such flow has infinite rank and that the absolute value of the jump of the roof function is a measure theoretic invariant. The main ingredient in the proofs is a Ranter type property of parabolic divergence of orbits of two nearby points in the flow direction.  Joint work with Adam Kanigowski.
Anton Solomko
University of Bristol
Event Location: 
Fine Hall 1001