### Boole’s Rings

- A countable ordinal definable set of reals without ordinal definable elements January 20, 2017 Victoria Gitman
- Regula Krapf, Ph.D. 2017, University of Bonn January 12, 2017 Joel David Hamkins
- Set-theoretic geology and the downward directed grounds hypothesis, Bonn, January 2017 January 10, 2017 Joel David Hamkins
- My Mathematics Genealogy January 4, 2017 Dana C. Ernst
- Transfinite game values in infinite chess, including new progress, Bonn, January 2017 January 3, 2017 Joel David Hamkins

### Comments on Boole’s Rings

- Comment on A countable ordinal definable set of reals without ordinal definable elements by Victoria Gitman January 21, 2017 Comments for Victoria Gitman
- Comment on A countable ordinal definable set of reals without ordinal definable elements by Robert Solovay January 20, 2017 Comments for Victoria Gitman
- Comment on There are no nondegenerate regular polygons in the integer lattice, except for squares by Joel David Hamkins January 17, 2017 Comments for Joel David Hamkins
- Comment on There are no nondegenerate regular polygons in the integer lattice, except for squares by Pierre B. January 17, 2017 Comments for Joel David Hamkins
- Comment on Math for nine-year-olds: fold, punch and cut for symmetry! by Fold Your Way to Glory – Study Score Calc January 14, 2017 Comments for Joel David Hamkins

# Tag Archives: Reverse Mathematics

## Computable roots of computable functions

Here are several interesting results from computable analysis: Theorem 1. If $f$ is a computable function from $\mathbb{R}$ to $\mathbb{R}$ and $\alpha$ is an isolated root of $f$, then $\alpha$ is computable. Corollary 2. If $p(x)$ is a polynomial over … Continue reading

## 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