### Boole’s Rings

- On conjugacy problems for graphs and trees October 11, 2019 Samuel Coskey
- (with Y. Hayut) Perfect Subtree Property for Weakly Compact Cardinals October 10, 2019 Sandra Müller
- Structural properties of the stable core October 10, 2019 Victoria Gitman
- Ground model definability in ${\rm ZF}$ October 10, 2019 Victoria Gitman
- (with S.-D. Friedman and V. Gitman) Structural Properties of the Stable Core October 4, 2019 Sandra Müller

### Comments on Boole’s Rings

- Comment on Solution to my transfinite epistemic logic puzzle, Cheryl’s Rational Gifts by Cheryl’s Rational Gifts: transfinite epistemic logic puzzle challenge! | Joel David Hamkins October 14, 2019 Comments for Joel David Hamkins
- Comment on The propagation of error in classical geometry constructions by Paul Alberti-Strait October 9, 2019 Comments for Joel David Hamkins
- Comment on The modal logic of arithmetic potentialism and the universal algorithm by The $Sigma_1$-definable universal finite sequence | Joel David Hamkins September 30, 2019 Comments for Joel David Hamkins
- Comment on I know that you know that I know that you know…. Oxford, October 2019 by Joel David Hamkins September 25, 2019 Comments for Joel David Hamkins
- Comment on I know that you know that I know that you know…. Oxford, October 2019 by charlie sitler September 25, 2019 Comments for Joel David Hamkins

# Category Archives: Research

## Reverse Mathematics of Matroids

This post is about the paper Reverse Mathematics of Matroids by Jeff Hirst and me. We look at basis theorems for countable vector spaces, countable graphs, and countable enumerated matroids. These three kinds of structures turn out to be extremely … Continue reading

Posted in Papers, Research
Leave a comment

## Talk on the existence of connected components of graphs

This week I am attending a seminar at Dagstuhl on Measuring the Complexity of Computational Content: Weihrauch Reducibility and Reverse Analysis. This post has slides from my talk and some blog-only remarks to expand on them.

Posted in Research, Talks
Leave a comment

## Talk on Reverse Mathematics and the Modal Logic of Reverse Mathematics

This is a transcription of notes from a talk I gave on November 1, 2013 to the interdisciplinary logic seminar at the University of Connecticut. I gave a general introduction to Reverse Mathematics and then spoke about my work with … Continue reading

Posted in Research, Talks
3 Comments

## Internal combinatorics and uniform reducibility

This post is a set of notes from a talk I gave on December 5th for the discrete mathematics seminar at Marshall University. I want to argue that logical analysis can reveal the “internal combinatorics” of theorems, using some recent … Continue reading

Posted in Musings, Research, Talks
Leave a comment

## An incompleteness theorem for β_{n} models

My first paper was “An incompleteness theorem for $\beta_n$ models” with Stephen Simpson [1]. It’s a short paper, but the idea is very pretty. We know that the incompleteness theorem implies there are strange models of arithmetic, but these models … Continue reading

Posted in Papers, Research
2 Comments

## The logic of Reverse Mathematics

This post is about a research idea I have been thinking about which is quite different from my usual research. It’s an example of a project with an “old fashioned” feel to it, as if it could have been studied … Continue reading