A Proof-Theoretic Approach to Slow Consistency

Anton Freund, University of Leeds. Part of the proofs, constructions and computations seminar series.

The slow consistency statement for Peano Arithmetic, due to S.-D. Friedman, Rathjen and Weiermann, is strictly weaker than the usual consistency statement (but still unprovable in Peano Arithmetic). So far, all proofs of this fact use model-theoretic results of Solovay or Sommer. I will present a new argument that relies on proof-theoretic methods, thus extending the toolbox for further applications.

Anton Freund, University of Leeds