Logic Week with Joel David Hamkins

Speak for Fudan Logic Seminar

On July 23, Prof. Hamkins will speak for #Fudan Logic Seminar#.

Time: 14:30 - 15:30

Computable surreal numbers

I shall give an account of the theory of computable surreal numbers, proving that these form a real-closed field. Which real numbers arise as computable surreal numbers? You may be surprised to learn that some noncomputable real numbers are computable as surreal numbers, and indeed the computable surreal real numbers are exactly the hyperarithmetic reals. More generally, the computable surreal numbers are exactly those with a hyperarithmetic surreal sign sequence. This is joint work with Dan Turetsky, but we subsequently found that it is a rediscovery of earlier work of Jacob Lurie.

Course on Philosophy of Mathematics

Joel David Hamkins, Ruizhi Yang

Time: 13:00 - 15:35 every Monday, Tuesday and Thursday from June 30 to July 25, 2025

Location: H6308

Professor Hamkins's lectures will start from July 7.

Slides for the first three meetings with Ruizhi Yang: Slides 01 Slides 02 Slides 03

The course is part of Fudan University International Summer Session.