### Boole’s Rings

- Inclusion modulo nonstationary June 20, 2019 Assaf Rinot
- Tuna Altinel June 6, 2019 Nick Gill
- Completely ineffable cardinals June 5, 2019 Victoria Gitman
- Some cute observations about computably saturated models June 4, 2019 Victoria Gitman
- Alan Turing’s theory of computation, Oxford and Cambridge Club, June 2019 June 2, 2019 Joel David Hamkins

### Comments on Boole’s Rings

- Comment on How to count by Joel David Hamkins May 30, 2019 Comments for Joel David Hamkins
- Comment on How to count by A witness to the writhing void May 29, 2019 Comments for Joel David Hamkins
- Comment on 50 Years of Set Theory in Toronto, May 2019 by saf May 26, 2019 Comments for Assaf Rinot
- Comment on The multiverse view in set theory, Singapore 2011 by A multiverse perspective on the axiom of constructiblity | Joel David Hamkins May 20, 2019 Comments for Joel David Hamkins
- Comment on Modal principles of potentialism, Oxford, January 2018 by David Roberts May 12, 2019 Comments for Joel David Hamkins

# Category Archives: Results worth knowing

## An example with Dedekind cuts

In this post, I will briefly describe an example in computability theory that is well known, but not easy to find in the literature. It gives one reason why Dedekind cuts are difficult to work with computationally. Theorem. There is … Continue reading

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## Filter quantifiers

I have been supervising an undergraduate student in an independent study in topology this semester. We have just finished the Stone–Čech compactification, and the semester is ending, so I want to end with an ultrafilter based proof of Hindman’s theorem. … Continue reading

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## 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