PSU Mark
Eberly College of Science Mathematics Department

Meeting Details

For more information about this meeting, contact Stephen Simpson.

Title:Invariant measures, computability, and reverse mathematics
Seminar:Logic Seminar
Speaker:Stephen G. Simpson, Pennsylvania State University
Abstract:
Let S be the unit circle. We construct a computable homeomorphism f: S --> S such that no computable probability measure on S is invariant under f. This construction is due to Mathieu Hoyrup and Cristobal Rojas. We extend their method to prove the following result of reverse mathematics: WKL_0 is equivalent over RCA_0 to the statement that for every Z-action on a compact metric space there exists an invariant probability measure.

Room Reservation Information

Room Number:MB315
Date:02 / 16 / 2010
Time:02:30pm - 03:45pm