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We show that Dependent Choice is a sufficient choice principle for developing the basic theory of proper forcing, and for deriving generic absoluteness for the Chang model in the presence of large cardinals, even with respect to…

Logic · Mathematics 2023-06-22 David Asperó , Asaf Karagila

We deal with an iteration theorem of forcing notion with a kind of countable support of nice enough forcing notion which is proper aleph_2-c.c. forcing notions. We then look at some special cases (Q_D 's preceded by random forcing).

Logic · Mathematics 2007-05-23 Saharon Shelah

The technique of "classical realizability" is an extension of the method of "forcing"; it permits to extend the Curry-Howard correspondence between proofs and programs, to Zermelo-Fraenkel set theory and to build new models of ZF, called…

Logic in Computer Science · Computer Science 2018-03-20 Jean-Louis Krivine

I prove forcing preservation theorems for products of definable partial orders preserving the cofinality of the meager or null ideal. Rectangular Ramsey theorems for related ideals follow from the proofs.

Logic · Mathematics 2007-05-23 Jindrich Zapletal

Forcing was first introduced by Paul J. Cohen in his work on the independence of the Continuum Hypothesis. Other formulations of forcing appeared using Model Theory, Boolean-valued Models, and Topos Theory. There is a folkloric claim that…

Logic · Mathematics 2026-05-27 Michel Viana Smykalla , Hugo Luiz Mariano

We study principles of the form: if a name $\sigma$ is forced to have a certain property $\varphi$, then there is a ground model filter $g$ such that $\sigma^g$ satisfies $\varphi$. We prove a general correspondence connecting these name…

Logic · Mathematics 2021-10-25 Philipp Schlicht , Christopher Turner

We consider extensions of the language of Peano arithmetic by transfinitely iterated truth definitions satisfying uniform Tarskian biconditionals. Without further axioms, such theories are known to be conservative extensions of the original…

Logic · Mathematics 2019-10-31 Lev D. Beklemishev , Fedor N. Pakhomov

We develop the theory of partial satisfaction relations for structures that may be proper classes and define a satisfaction predicate appropriate to such structures. We indicate the utility of this theory as a framework for the development…

Logic · Mathematics 2012-02-17 Robert A. Van Wesep

We give a brief survey on the interplay between forcing axioms and various other non-constructive principles widely used in many fields of abstract mathematics, such as the axiom of choice and Baire's category theorem. First of all we…

Logic · Mathematics 2019-12-03 Matteo Viale

In the first part of this paper, we consider several natural axioms in urelement set theory, including the Collection Principle, the Reflection Principle, the Dependent Choice scheme and its generalizations, as well as other axioms…

Logic · Mathematics 2024-11-20 Bokai Yao

These notes present a compact and self-contained approach to iterated forcing with a particular emphasis on semiproper forcing. We tried to make our presentation accessible to any scholar who has some familiarity with forcing and boolean…

Logic · Mathematics 2014-02-10 Matteo Viale , Giorgio Audrito , Silvia Steila

It is shown that the boldface maximality principle for subcomplete forcing, together with the assumption that the universe has only set-many grounds, implies the existence of a (parameter-free) definable well-ordering of…

Logic · Mathematics 2018-02-15 Gunter Fuchs

The foundations of forcing theory are reworked to streamline the presentation and to show how the most basic results are applicable in very general contexts.

Logic · Mathematics 2007-12-13 Peter M. Johnson

In the Zermelo--Fraenkel set theory with the Axiom of Choice a forcing notion is "$\kappa$-distributive" if and only if it is "$\kappa$-sequential". We show that without the Axiom of Choice this equivalence fails, even if we include a weak…

Logic · Mathematics 2022-12-22 Asaf Karagila , Jonathan Schilhan

These are lecture notes from a course I gave at the University of Wisconsin during the Spring semester of 1993. Part 1 is concerned with Borel hierarchies. Section 13 contains an unpublished theorem of Fremlin concerning Borel hierarchies…

Logic · Mathematics 2009-09-25 Arnold Miller

If T has only countably many complete types, yet has a type of infinite multiplicity then there is a ccc forcing notion Q such that, in any Q --generic extension of the universe, there are non-isomorphic models M_1 and M_2 of T that can be…

Logic · Mathematics 2007-05-23 Michael C. Laskowski , Saharon Shelah

We study methods to obtain the consistency of forcing axioms, and particularly higher forcing axioms. We first force over a model with a supercompact cardinal $\theta>\kappa$ to get the consistency of the forcing axiom for $\kappa$-strongly…

Logic · Mathematics 2024-03-19 David Asperó , Sean Cox , Asaf Karagila , Christoph Weiss

Ordinary and transfinite recursion and induction and ZF set theory are used to construct from a fully interpreted object language and from an extra formula a new language. It is fully interpreted under a suitably defined interpretation.…

Logic · Mathematics 2017-12-15 Seppo Heikkilä

Extending Mart\'in Escard\'o's effectful forcing technique, we give a new proof of a well-known result: Brouwer's monotone bar theorem holds for any bar that can be realized by a functional of type $(\mathbb{N} \to \mathbb{N}) \to…

Logic · Mathematics 2022-02-23 Jonathan Sterling

The purpose of this article is to give a presentation of the method of forcing aimed at someone with a minimal knowledge of set theory and logic. The emphasis will be on how the method can be used to prove theorems in ZFC.

Logic · Mathematics 2019-02-11 Justin Tatch Moore