Cohen forcing and inner models, (2020). Math. Log. Quart., 66: 65-72. doi:10.1002/malq.201800062, arXiv Inner mantles and iterated HOD, with Kameryn J. Williams, (2019), . Math. Log. Quart., 65: 498-510. doi:10.1002/malq.201800071. arXiv Inner-model reflection principles, with Neil Barton, Andres Caicedo, Gunter Fuchs, Joel David Hamkins and Ralf Schindler, Stud. Logica (2019). ; pdf, arXiv...
The Ground Axiom
Dissertation: The Ground Axiom
![Cracked earth](https://openlab.citytech.cuny.edu/jonasreitz/files/2024/06/DryCrackedGround-oleg-mitiukhin-VkHqO8-VybU-unsplash-755x515.jpg)
Unforcing and the Ground Axiom My interest in “unforcing,” somehow working backwards from a forcing extension to a ground model, started early in my set theory studies. When I went through the rite of passage of learning Paul Cohen’s forcing – an exercise in induction, with a lovely (and at the time, frustratingly opaque) back-and-forth between technical details and...
Inner-Model Reflection Principles
![A lit up object sitting on top of a table](https://openlab.citytech.cuny.edu/jonasreitz/files/2019/11/chay-kelly-zzeWQXR2MWc-unsplash-small.jpg)
This paper has its origins in a question by Neil Barton on Math.SE, “What is the consistency strength of width-reflection?” Start with one of the foundational relationships of set theory, that of height-reflection — any property true in the universe $V$ is true in some initial segment $V_\kappa$. Then “rotate your head ninety degrees” and consider the corresponding...