Ronald B. Jensen

We are deeply saddened to report the death of Ronald Jensen. Ronald passed away on September 16, 2025.

Those who wish to share their sympathies or memories are kindly invited to send messages of condolence to Ronny2025@gmx.net.

Postal Address:
Humboldt-Universität zu Berlin
Institut für Mathematik
Sitz: Rudower Chaussee 25
D-10099 Berlin
e-mail: jensen@mathematik.hu-berlin.de

Joint Work with Qi Feng

Type 1 Mice (PDF)

Joint Work with John Steel

K without the Measurable (PDF)

Lectures given at the 2012 AII Summer School in Singapore

Subcomplete Forcing and L-Forcing (PDF)

Handwritten Notes

Available as PDF

Measures of order Zero

Chapter 1 (PDF: 1, 1.A, 2, 3, 4, 5)
Chapter 2 (PDF: 1, 2, 3, 4)
Chapter 3 (PDF: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
Appendix (PDF: 1,2)

A New Fine Structure

Introduction (PDF)
Chapter 1 (PDF)
Chapter 2 (PDF)
Chapter 3 (PDF)
Chapter 4 (PDF)
Chapter 5 (PDF)
Chapter 5 - Appendix (PDF)
Chapter 6 (PDF)
Chapter 7 (PDF)
Chapter 7 - Appendix (PDF)
Chapter 8 (PDF)
Chapter 8 - Appendix (PDF)
Chapter 9 (PDF)
Chapter 10 (PDF)
Chapter 11 (PDF)

Addendum to A New Fine Structure

Introduction (PDF)
Chapter 1 (PDF)
Chapter 2 (PDF)
Chapter 3 (PDF)

Corrections and Remarks

Introduction (PDF)
Chapter 2 (PDF)
Chapter 2 (PDF)
Chapter 2 - Addendum (PDF)
Chapter 2 - Correction (PDF)
Chapter 3 (PDF)
Chapter 4 (PDF)
Chapter 5 (PDF)
Chapter 6 (PDF)
Chapter 7 + 8 (PDF)
Addendum (Zeman's proof) (PDF)

More on Iterability

Introduction (PDF)
Chapter 1 (PDF)
Chapter 2 (PDF)
Chapter 3 (PDF)

T-Mice

Introduction (PDF)
Chapter 1 (PDF)
Chapter 2 (PDF)
Chapter 3 (PDF)
Chapter 4 (PDF)
A Correction to T-Premice (PDF)

L-Forcing

Introduction (PDF)
Chapter 1 (PDF)
Chapter 2 (PDF)
Chapter 3 (PDF)
Chapter 4 (PDF)
Chapter 5 (PDF)
Appendix to Chapter 5 (PDF)
Chapter 6 (PDF)
Some Problems of Mitchell et al. (PDF)

Some Combinatorial Properties of L and V

Introduction (PDF)
Chapter 1 (PDF)
Chapter 2 (PDF)

Robust Extenders

Introduction (PDF )
Chapter 1 (PDF)
A Correction to Chapter 1 (PDF)
Chapter 2 (PDF)
Chapter 3 (PDF)
Addendum (PDF)

Subproper and Subcomplete Forcing

Introduction (PDF)
Chapter 1: Preliminaries (PDF)
Chapter 2: Iterating SPSCF (PDF)
Chapter 3: Examples (PDF)
Appendix (PDF)

Remarks on the Two Cardinal Problem

Introduction (PDF)
Chapter 1: Remarks on the gap two problem (PDF)
Chapter 2: Forcing to obtain a diamond^plus-sequence from a diamond-sequence (PDF)
Dissertation Räsch: On the Failure of the GAP-1 Transfer Property ( Summary, TOC, 1, 2, 3, 4, 5, 6, 7, 8, Appendix)

The Extended Namba Problem

Introduction (PDF)
Chapter 1: An Interation Theorem (PDF)
Chapter 2: Preliminaries (PDF)
Chapter 3: The Successor Step (PDF)
Chapter 4: The Limit Case (PDF)

Iteration Theorems for Subcomplete and Related Forcings

Introduction (PDF)
Chapter 1: Preliminaries (PDF)
Chapter 2: Subcomplete Forcings (PDF)
Chapter 3: Variations (PDF)
Chapter 4: Subproper Forcing (PDF)
Chapter 5: Semi-Subproper Forcing (PDF)

Admissible Sets

Preface (PDF)
Chapter 0: Preliminaries (PDF)
Chapter 1 (PDF)
Chapter 2 (PDF)
Chapter 3 (PDF)
Chapter 4 (PDF)
Chapter 5 (PDF)
Chapter 6 (PDF)

Dee Subproper Forcing

Intro + Bibliography (PDF)
Chapter 1 (PDF)
Chapter 2 (PDF)
Chapter 3 (PDF)
Chapter 4 (PDF)
Appendix (PDF)

Forcing Axioms compatible with CH

Intro + Bibliography (PDF)
Chapter 1 (PDF)
Chapter 2 (PDF)
Chapter 3 (PDF)
Chapter 4 (PDF)

What is the strength of two cofinal well founded branches?

Intro (PDF)
Chapter 1 (PDF)
Chapter 2 (PDF)
Chapter 3 (PDF)
Chapter 4 (PDF)
Chapter 5 (PDF)

Almost Subcomplete Forcing

Preface (PDF)
Chapter 1.1 (PDF)
Chapter 1.2 (PDF)

On the Subcompleteness of some Variants of Namba Forcing

Chapter 1 (PDF)
Chapter 2 (PDF)
Chapter 3 (PDF)
Chapter 4 (PDF)
Chapter 5 (PDF)
Chapter 6 (PDF)

Manuscript on fine structure, inner model theory, and the core model below one Woodin cardinal

Script Version 26th September 2016 (PDF)

Smooth iterations

Introduction (PDF)
Chapter 1 (PDF)
Chapter 2 (PDF)
Chapter 3 (PDF)
Chapter 4 (PDF)
Chapter 5 (PDF)
Chapter 6 (PDF)
Chapter 7 (PDF)
Addendum (PDF)
Bibliography 7 (PDF)
Errata (PDF)

Book: Manuscript on fine structure, inner model theory, and the core model below one Woodin cardinal

Jensen_Manuscript_Frontpage__Index (PDF)
Jensen_Manuscript_Chapter_0_Preliminaries (PDF)
Jensen_Manuscript_Chapter_1_Transfinite_Recursion_Theory) (PDF)
Jensen_Manuscript_Chapter_2_Basic_Fine_Structure_Theory (PDF)
Jensen_Manuscript_Chapter_3_Mice (PDF)
Jensen_Manuscript_Chapter_4_Properties_of_Mice (PDF)
Jensen_Manuscript_Chapter_5_The_model_Kc (PDF)
Jensen_Manuscript_Bibliography (PDF)
Jensen_Manuscript_2024 (PDF)

Last changed: September, 2025