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We show that for a Suslin ccc forcing notion $\mathbb Q$ adding a Hechler real, ``$\text{ZF}+\text{DC}_{\omega_1}+$all sets of reals are $I_{\mathbb Q,\aleph_0}$-measurable'' implies the existence of an inner model with a measurable…

Logic · Mathematics 2023-01-03 Mohammad Golshani , Haim Horowitz , Saharon Shelah

This dissertation surveys several topics in the general areas of iterated forcing, infinite combinatorics and set theory of the reals. There are two parts. In the first half I consider alternative versions of the Cicho\'n diagram. First I…

Logic · Mathematics 2020-08-12 Corey Bacal Switzer

We show that certain type of tree forcings, including Sacks forcing, increases the covering of the strong measure zero ideal $\mathcal{SN}$. As a consequence, in Sacks model, such covering number is equal to the size of the continuum, which…

Logic · Mathematics 2019-02-06 Miguel A. Cardona , Diego A. Mejía , Ismael E. Rivera-Madrid

Shelah-Woodin investigate the possibility of violating instances of $GCH$ through the addition of a single real. In particular they show that it is possible to obtain a failure of $CH$ by adding a single real to a model of $GCH$, preserving…

Logic · Mathematics 2015-10-13 Sy David Friedman , Mohammad Golshani

We prove that the Sacks forcing collapses the continuum onto the dominating number d, answering the question of Carlson and Laver. Next we prove that if a proper forcing of the size at most continuum collapses omega_2 then it forces…

Logic · Mathematics 2009-09-25 Andrzej Rosłanowski , Saharon Shelah

The notion of $\theta$-FAM-linkedness, introduced in the second author's master thesis, is a formalization of the notion of strong FAM limits for intervals, whose initial form and applications have appeared in the work of Saharon Shelah,…

Logic · Mathematics 2025-07-16 Diego A. Mejía , Andrés F. Uribe-Zapata

In this paper we answer several questions in arXiv:2102.06009 regarding density variants of Mathias and Silver forcing. These questions include whether each of the forcing is proper, add dominating real, or add Cohen real. We also…

Logic · Mathematics 2025-07-25 Shixiao Liu

I introduce a new family of axioms extending ZFC set theory, the $\Sigma_n$-correct forcing axioms. These assert roughly that whenever a forcing name $\dot{a}$ can be forced by a poset in some forcing class $\Gamma$ to have some $\Sigma_n$…

Logic · Mathematics 2024-05-17 Ben Goodman

We study the cardinal invariants of measure and category after adding one random real. In particular, we show that the number of measure zero subsets of the plane which are necessary to cover graphs of all continuous functions maybe large…

Logic · Mathematics 2016-09-06 Tomek Bartoszyński , Andrzej Rosłanowski , Saharon Shelah

In \cite{MV} we defined and proved the consistency of the principle ${\rm GM}^+(\omega_3,\omega_1)$ which implies that many consequences of strong forcing axioms hold simultaneously at $\omega_2$ and $\omega_3$. In this paper we formulate a…

Logic · Mathematics 2024-12-30 Rahman Mohammadpour , Boban Velickovic

We give an application of our extender based Radin forcing to cardinal arithmetic. Using a preparation forcing and interleaving of Cohen and Levy forcings in the normal Radin sequence we get a model with a power function having a fixed…

Logic · Mathematics 2007-05-23 Carmi Merimovich

We present a direct construction of stationary set preserving forcings that make $\omega$-cofinal all the members of some arbitrary set $\mathcal{K}$ of regular cardinals $\kappa > \omega_1$. In addition, it is made possible to ensure that…

Logic · Mathematics 2025-10-29 Ben De Bondt , Boban Velickovic

We present two ways in which the model $L({\mathbb R})$ is canonical assuming the existence of large cardinals. We show that the theory of this model, with {\em ordinal} parameters, cannot be changed by small forcing; we show further that a…

Logic · Mathematics 2007-05-23 Itay Neeman , Jindrich Zapletal

Consider $(\kappa^{+++},\kappa^{++}) \twoheadrightarrow (\kappa^+,\kappa)$ where $\kappa$ is an uncountable regular cardinal. By a result of Shelah's we have $\operatorname{cof}(X \cap \kappa^{++}) = \kappa$ for almost all $X \subset…

Logic · Mathematics 2020-03-26 Dominik Adolf

Since being isolated by Viale and Weiss in 2009, the Guessing Model Property has emerged as a particularly prominent and powerful consequence of the Proper Forcing Axiom. In this paper, we investigate connections between variations of the…

Logic · Mathematics 2023-03-03 Chris Lambie-Hanson , Šárka Stejskalová

Let l^0 and m^0 be the ideals associated with Laver and Miller forcing, respectively. We show that add (l^0) < cov(l^0) and add (m^0) < cov(m^0) are consistent. We also show that both Laver and Miller forcing collapse the continuum to a…

Logic · Mathematics 2008-02-03 Martin Goldstern , Miroslav Repicky , Saharon Shelah , Otmar Spinas

Based on the work of Shelah, Kellner, and T\u{a}nasie (Fund. Math., 166(1-2):109-136, 2000 and Comment. Math. Univ. Carolin., 60(1):61-95, 2019), and the recent developments in the third author's master's thesis, we develop a general theory…

Logic · Mathematics 2024-10-24 Miguel A. Cardona , Diego A. Mejía , Andrés F. Uribe-Zapata

The main result of this paper is a partial answer to [math.LO/9909115, Problem 5.5]: a finite iteration of Universal Meager forcing notions adds generic filters for many forcing notions determined by universality parameters. We also give…

Logic · Mathematics 2013-01-04 Andrzej Roslanowski , Saharon Shelah

Assume $\kappa = \kappa^{< \kappa}$ (usually $\aleph_0$ or an inaccessible). We shall deal with iterated forcings preserving ${}^{\kappa>}{\rm Ord}$ and not collapsing cardinals along a linear order $L$. A sufficient condition for this,…

Logic · Mathematics 2026-03-19 Saharon Shelah

In this paper we first formulate several ``combinatorial principles'' concerning kappa \times omega matrices of subsets of omega and prove that they are valid in the generic extension obtained by adding any number of Cohen reals to any…

Logic · Mathematics 2010-03-17 I. Juhász , Lajos Soukup , Z. Szentmiklóssy