3 papers
math.LO2026
A Turing machine model for Kleene Type 2 recursion
Philip D Welch
We give an account of Kleene's Type 2 recursion theory modelled on Turing machines. We apply this account to observe that the feedback computation of \cite{AFL2020} is an example o…
math.LO2026
Higher Type ITTM-recursion and Determinacy of Infinite Games
Philip D Welch
We outline a theory of type 2 recursion for Infinite Time Turing Machines {\em à la Kleene}. We establish a connection between classical descriptive set theory and ittm theory, by…
math.LO2024
Of Mice and Machetes
Christopher Henney-Turner, Philip Welch
Let be the class of regular cardinals which are not hyperinaccessible. We show that , and similar inner models in the -inaccessible hierarchy, can be generated by ite…