AuthorJonas Reitz

Inner-Model Reflection Principles

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A lit up object sitting on top of a table

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...

Metro NExt 9/19: Subversive Compromise

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subversive monkeys

Subversive Compromise:Working in and around the system to write a grant, get funded, and make stuff happen. Metro NExT (New Experiences in Teaching) Workshop 2019September 13, 2019 – Courant/NYU (251 Mercer St.), Room 109 ABSTRACT:In this interactive workshop, participants will explore challenges, opportunities and lessons learned in conceiving, planning, designing, and writing a successful...

Generalized Cohen Iterations

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Set Theory Seminar (RESCHEDULED from April 12)CUNY Graduate Center, Room 6417Friday, May 17, 10:00-11:45am, 2019Jonas Reitz, CUNYGeneralized Cohen Iterations Adding Cohen subsets to each of a class of cardinals in turn is a common construction in set theory, and underlies many fundamental results. The construction comes in two basic flavors, products (as in Easton’s Theorem on the powers of...

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