Fine structure from normal iterability
Abstract
We show that (i) the standard fine structural properties for premice follow from normal iterability (whereas the classical proof relies on iterability for stacks of normal trees), and (ii) every mouse which is finitely generated above its projectum, is an iterate of its core. That is, let be an integer and let be an -sound, -iterable premouse. Then (i) is -solid and -universal, condensation holds for , and if then is super-Dodd-sound, a slight strengthening of Dodd-soundness. And (ii) if there is such that is the -hull of parameters in , then is a normal iterate of its -core ; in fact, there is an -maximal iteration tree on , of finite length, such that , and is just the core embedding. Applying fact (ii), we prove that if is a mouse and is a ground of via a strategically -closed forcing , and if (that is, the initial segment of of height is in ), then the forcing is trivial; that is, . And if there is a measurable cardinal, then there is a non-solid premouse. The results hold for premice with Mitchell-Steel indexing, allowing extenders of superstrong type to appear on the extender sequence.
Keywords
Cite
@article{arxiv.2011.10037,
title = {Fine structure from normal iterability},
author = {Farmer Schlutzenberg},
journal= {arXiv preprint arXiv:2011.10037},
year = {2025}
}
Comments
145 pages. Made minor corrections to proof of Theorem 11.3. (Especially Claim 2's proof; the earlier version appeared to be using stronger hypotheses than those available. Otherwise mostly corrected typos in the proof. Added footnote on page 92.)