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Various theorems for the preservation of set-theoretic axioms under forcing are proved, regarding both forcing axioms and axioms true in the Levy-Collapse. These show in particular that certain applications of forcing axioms require to add…

Logic · Mathematics 2007-05-23 Bernhard Koenig

We prove that any countable support iteration formed with posets with $\omega_2$-p.i.c.\ has $\omega_2$-c.c., assuming CH in the ground model and assuming also that $\omega_1$ is not collapsed. This improves earlier results of Shelah by…

Logic · Mathematics 2016-09-07 Chaz Schlindwein

Assuming the P-ideal dichotomy, we attempt to isolate those cardinal characteristics of the continuum that are correlated with two well-known consequences of the proper forcing axiom. We find a cardinal invariant $\mathfrak{x}$ such that…

Logic · Mathematics 2013-05-27 Dilip Raghavan , Stevo Todorcevic

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

We prove some iteration theorems for a certain class of $\kappa^+$-cc forcing posets.

Logic · Mathematics 2018-11-14 James Cummings , Mirna Džamonja , Itay Neeman

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

Vladimir Kanovei \cite{zbMATH01335192} developed the technique of geometric iteration and used it to prove that the perfect set forcing can be iterated with countable supports along any partial order, while preserving $\aleph_1$. In…

Logic · Mathematics 2026-04-14 Mirna Džamonja

We bring forward a logical system of transition algebras that enhances many-sorted first-order logic using features from dynamic logics. The sentences we consider include compositions, unions, and transitive closures of transition…

Logic in Computer Science · Computer Science 2024-04-26 Hashimoto Go , Daniel Găină , Ionuţ Ţuţu

We define forcing orders which add witnesses to the failure of various forms of Friedman's Property. These posets behave similarly to the forcing order adding a nonreflecting stationary set but have the advantage of allowing the…

Logic · Mathematics 2024-11-05 Hannes Jakob

We outline a portfolio of novel iterable properties of c.c.c. and proper forcing notions and study its most important instantiations, Y-c.c. and Y-properness. These properties have interesting consequences for partition-type forcings and…

Logic · Mathematics 2017-03-07 David Chodounský , Jindřich Zapletal

We introduce a method of constructing a forcing along a simplified $(\kappa,1)$-morass such that the forcing satisfies the $\kappa$-chain condition. Alternatively, this may be seen as a method to thin out a larger forcing to get a chain…

Logic · Mathematics 2008-10-30 Bernhard Irrgang

The bounded proper forcing axiom BPFA is the statement that for any family of aleph_1 many maximal antichains of a proper forcing notion, each of size aleph_1, there is a directed set meeting all these antichains. A regular cardinal kappa…

Logic · Mathematics 2016-09-06 Martin Goldstern , Saharon Shelah

We present a systematic study of the method of "norms on possibilities" of building forcing notions with keeping their properties under full control. This technique allows us to answer several open problems, but on our way to get the…

Logic · Mathematics 2013-01-03 Andrzej Roslanowski , Saharon Shelah

Consider a periodically forced nonlinear system which can be presented as a collection of smaller subsystems with pairwise interactions between them. Each subsystem is assumed to be a massive point moving with friction on a compact surface,…

Dynamical Systems · Mathematics 2015-09-25 Ivan Polekhin

We develop a forcing poset with finite conditions which adds a partial square sequence on a given stationary set, with adequate sets of models as side conditions. We then develop a kind of side condition product forcing for simultaneously…

Logic · Mathematics 2018-10-26 John Krueger

We introduce bounded category forcing axioms for well-behaved classes $\Gamma$. These are strong forms of bounded forcing axioms which completely decide the theory of some initial segment of the universe $H_{\lambda_\Gamma^+}$ modulo…

Logic · Mathematics 2021-01-11 David Aspero , Matteo Viale

We introduce a forcing technique to construct three-dimensional arrays of generic extensions through FS (finite support) iterations of ccc posets, which we refer to as 3D-coherent systems. We use them to produce models of new constellations…

Logic · Mathematics 2017-03-30 Vera Fischer , Sy D. Friedman , Diego A. Mejía , Diana C. Montoya

This paper presents the main results in my Ph.D. thesis. In what follows several proofs of SCH are presented introducing a family of covering properties which implies both SCH and the failure of various forms of square. These covering…

Logic · Mathematics 2007-05-23 Matteo Viale

We give a forcing construction of the square principle on omega_1 using forcing with conditions whose domain is finite.

Logic · Mathematics 2016-08-14 Gregor K. Dolinar , Mirna Džamonja

We study a family of variants of Jensen's\emph{subcomplete forcing axiom}, $\mathsf{SCFA}$ and \emph{subproper forcing axiom}, $\mathsf{SubPFA}$. Using these we develop a general technique for proving non-implications of $\mathsf{SCFA}$,…

Logic · Mathematics 2025-08-06 Hiroshi Sakai , Corey Bacal Switzer