**Venue**: PovoZero, via Sommarive, 14 - Povo - Sala Seminari "-1"**Time**: 2:30

**Speaker**:

**Dávid Natingga**, PhD candidate - University of Leeds

**Abstract**:

An ordinal alpha is admissible iff alpha-th level L_alpha of Goedel's constructible hierarchy satisfies the axioms of Kripke-Platek set theory (roughly predicative part of ZFC). Alpha-computability theory is the study of the first-order definability theory over Goedel's L_alpha for an admissible ordinal alpha.

Equivalently, alpha-computability theory studies the computability on a Turing machine with a transfinite tape and time of an order type alpha for an admissible ordinal alpha. The field of alpha-computability theory is the source of deep connections between computability theory, set theory, model theory, definability theory and other areas of mathematics.

In the seminar I will assume basic familiarity with computability theory and axiomatic set theory. Other notions such as Goedel's constructible hierarchy and an admissible ordinal will be explained.

**Contact person: **** **Roberto Zunino