During November 4-8, 2019 I visited the University of Barcelona and
participated in a conference
on Proof
Theory, Modal Logic, and Reflection Principles (PMR). This
conference was also known as the ** Lustrum Wormshop**.

As part of the conference I gave an invited survey talk
on ** Degrees of unsolvability**.

My abstract is available in several formats: PDF, PS, DVI, LaTeX.

My slides are available in several formats: PDF, PS.

A list of my recent and upcoming talks is available.

My publication list is available.

t20@psu.edu / 11 November 2019