Peter Koepke

A notion of computability involving natural numbers can often be generalized to computability using ordinal numbers. We give a general overview of the field of ordinal computability and then concentrate on Infinite Time BlumShubSmale Machines (ITBM). We show that the set of ITBMcomputable reals coincides with the reals in the level L_{ωω} of Gödel's constructible universe. 