In April 2001, at the invitation of the University of Pisa, Italy, I attended a conference on Hilbert's Problems Today. The conference was devoted to a reexamination of Hilbert's famous 1900 problem list.
At the conference I gave an invited talk entitled The Gödel Hierarchy and Reverse Mathematics. My transparencies are available in several formats: DVI, PDF, PS.
My abstract is also available.
The basic reference on Reverse Mathematics is my book, Subsystems of Second Order Arithmetic.
My paper Partial Realizations of Hilbert's Program is available on my publications page.
I run FOM, an automated e-mail list for discussing foundations of mathematics.
t20@psu.edu / 10 April 2001