The metamathematics of \Pi^1_2 sentences

02.06.2022 15:00 - 16:30

J. Aguilera (TU Wien)

We will survey some recent results on the metamathematics of \(\Pi^1_2\) sentences. Most of the work involves a kind of Proof Theory analogous to classical ordinal analysis, but focused on a \(\Pi^1_2\) notion instead. The talk will be aimed at a general logic audience. Topics will include: proof-theoretic \(\Pi^1_2\)-norms, a characterization of the \(\Pi^1_2\) consequences of arithmetical comprehension and related systems, \(\Pi^1_2\)-soundness ordinals, and the \(\Pi^1_2\)-Spectrum Conjecture. This is joint work with F. Pakhomov.




HS 13, 2. OG., OMP 1