Por Emanuele Frittaion (University of Leeds).

We will recall Turing and Feferman's work on iterations of reflection principles over Peano Arithmetic. The main result here, due to Feferman, is that every true sentence of arithmetic can be proved in some "transfinite recursive iteration" of uniform reflection over Peano Arithmetic. We will then see what happens in the case of Heyting Arithmetic. Spoiler alert: Feferman's completeness result, as expected, fails in the intuitionistic case.

Zoom | Meeting ID: 837 8989 1971