My research interests mainly lie in inner model theory and determinacy.

In preparation

Published papers and preprints

This is a BSL review.

We show that in the Pmax extension of a certain Chang-type model of determinacy, if κ∈{ω1,ω2,ω3}, then the restriction of the club filter on κ∩Cof(ω) to HOD is an ultrafilter in HOD. This answers Question 4.11 of the paper "On ω-Strongly Measurable Cardinals" raised by Ben-Neria and Hayut.

Based on earlier work of the third author, we construct a Chang-type model with supercompact measures extending a derived model of a given hod mouse with a regular cardinal δ that is both a limit of Woodin cardinals and a limit of <δ-strong cardinals. The existence of such a hod mouse is consistent relative to a Woodin cardinal that is a limit of Woodin cardinals. We argue that our Chang-type model satisfies AD^+ + AD_R + Θ is regular + ω1 is <δ∞-supercompact for some regular cardinal δ∞>Θ. This complements Woodin's generalized Chang model, which satisfies AD^+ + AD_R + ω1 is supercompact, assuming a proper class of Woodin cardinals that are limits of Woodin cardinals.

Assuming the existence of a certain hod pair with a Woodin cardinal that is a limit of Woodin cardinals, we show that the Chang model satisfies AD^+ in any set generic extensions.

We show that if the universe is self-iterable and kappa is an inaccessible limit of Woodin cardinal then "AD_R + Theta is regular" holds in the derived model at kappa. The proof is fine-structure free, and only assumes basic knowledge of iteration trees and iteration strategies. Our proof can be viewed as the fine-structure free version of the well-known fact that "AD_R + Theta is regular" is true in the derived models of hod mice that have inaccessible limit of Woodin cardinals. However, the proof uses a different set of ideas and is more general. 

Notes

This note was written for a reading seminar of Steel's lecture note, "Introduction to Iterated Ultrapowers." Starting from the definition of iteration trees, I give a proof sketch of the branch existence theorem for iteration trees of length omega.

Week 1: Basic Analysis of the Pmax forcing. For example, it was shown that in any Pmax extension of an AD^+ model, the nonstationary ideal on omega_1 is saturated, delta^1_2 is omega_2, and the continuum is omega_2.

Week 2: Advanced results of the Pmax forcing. The following topics are included: Forcing MM^++(c) over models of "AD_R + Theta is regular." Overview of Larson and Sargsyan's result on failures of square principles in Pmax extensions. Some comments on Woodin's result on the equivalence of (*)^+ and (*)^++.

Selected Slides

These slides were used at Logic Colloquium 2023 on June 9, 2023. The talk is based on several joint works with N. Aksornthong, J. Holland, S. Müller and G. Sargsyan.

These are my slides used at Kobe Set Theory Seminar on May 15 & 22, 2023. This is joint work with S. Müller and G. Sargsyan. (May 31, 2023: the proof given in Part II contains an error. We correct the error in the preprint.)

This is a revised version of my slides used at Core Model Seminar on January 31, 2023. This is joint work with G. Sargsyan.

This is a revised version of my slides used at Core Model Seminar on January 24, 2023. In the slides, I give a proof outline of the main theorem in Sargsyan's paper, "Covering with Chang models over derived models."