### Boole’s Rings

- The rearrangement number: how many rearrangements of a series suffice to verify absolute convergence? Mathematics Colloquium at Penn, September 2016 July 30, 2016 Joel David Hamkins
- Set-theoretic geology and the downward-directed grounds hypothesis, CUNY Set Theory seminar, September 2016 July 30, 2016 Joel David Hamkins
- Crecimiento en grupos y otras estructuras July 19, 2016 Nick Gill
- More notions of forcing add a Souslin tree July 17, 2016 Assaf Rinot
- In praise of some history July 9, 2016 Asaf Karagila

### Comments on Boole’s Rings

- Comment on Set-theoretic geology and the downward-directed grounds hypothesis, CUNY Set Theory seminar, September 2016 by Joel David Hamkins July 30, 2016 Comments for Joel David Hamkins
- Comment on Set-theoretic geology and the downward-directed grounds hypothesis, CUNY Set Theory seminar, September 2016 by Joel David Hamkins July 30, 2016 Comments for Joel David Hamkins
- Comment on Set-theoretic geology and the downward-directed grounds hypothesis, CUNY Set Theory seminar, September 2016 by allenknutson July 30, 2016 Comments for Joel David Hamkins
- Comment on The rearrangement number: how many rearrangements of a series suffice to verify absolute convergence? Mathematics Colloquium at Penn, September 2016 by Ali Sadegh Daghighi July 30, 2016 Comments for Joel David Hamkins
- Comment on Set-theoretic geology and the downward-directed grounds hypothesis, CUNY Set Theory seminar, September 2016 by John Baez July 30, 2016 Comments for Joel David Hamkins

# Monthly Archives: January 2012

## 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
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## AMS/ASL Special Session on Alan Turing

I arrived home yesterday from the 2012 Joint Mathematics Meetings in Boston, where I was a co-organizer of the AMS/ASL Special Session on the Life and Legacy of Alan Turing. The talks were wonderful, and the session went very smoothly, … Continue reading

Posted in Meetings
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