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Related papers: 0^# and elementary end extensions of V_k

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We prove that every homogeneously Souslin set is coanalytic provided that either (a) 0^long does not exist or else (b) V=K where K is the core model below a \mu-measurable cardinal.

Logic · Mathematics 2007-05-23 Peter Koepke , Ralf Schindler

Let L be a countable and locally finite CW complex. Suppose that the class of all metrizable compacta of extension dimension not greater than L contains a universal element which is an absolute extensor in dimension L. Our main result shows…

Geometric Topology · Mathematics 2007-05-23 Alex Karasev , Vesko Valov

In this article we proved so-called strong reflection principles corresponding to formal theories Th which has omega-models. An posible generalization of the Lob's theorem is considered.Main results is: (1) let $k$ be an inaccessible…

General Mathematics · Mathematics 2019-10-08 Jaykov Foukzon

We prove that every point-finite family of nonempty functionally open sets in a topological space $X$ has the cardinality at most an infinite cardinal $\kappa$ if and only if $w(X)\leq\kappa$ for every Valdivia compact space $Y\subseteq…

General Topology · Mathematics 2015-12-25 V. V. Mykhaylyuk

For an uncountable regular cardinal \kappa we let \nabla_\kappa(A) be the statement that A \subset \kappa and for all regular \theta > \kappa, the set of all X \in [\theta]^<\kappa such that X \cap \kappa \in \kappa and otp(X \cap OR) is a…

Logic · Mathematics 2007-05-23 Ralf Schindler

The weakly compact reflection principle $\text{Refl}_{\text{wc}}(\kappa)$ states that $\kappa$ is a weakly compact cardinal and every weakly compact subset of $\kappa$ has a weakly compact proper initial segment. The weakly compact…

Logic · Mathematics 2017-09-05 Brent Cody , Hiroshi Sakai

We present two different types of models where, for certain singular cardinals lambda of uncountable cofinality, lambda -> (lambda, omega+1)^2, although lambda is not a strong limit cardinal. We announce, here, and will present in a…

Logic · Mathematics 2016-09-07 Saharon Shelah , Lee Stanley

Assume ZF (without the Axiom of Choice). Let $j:V_\varepsilon\to V_\delta$ be a non-trivial $\in$-cofinal $\Sigma_1$-elementary embedding, where $\varepsilon,\delta$ are limit ordinals. We prove some restrictions on the constructibility of…

Logic · Mathematics 2020-12-21 Farmer Schlutzenberg

For an abstract elementary class $\mathbf{K}$ and a cardinal $\lambda \geq LS(\mathbf{K})$, we prove under mild cardinal arithmetic assumptions, categoricity in two succesive cardinals, almost stability for $\lambda^+$-minimal types and…

Logic · Mathematics 2024-09-06 Marcos Mazari-Armida , Sebastien Vasey , Wentao Yang

Suppose that ${\mathcal M}$ is a model of PA and ${\mathcal N}$ is a countably generated elementary end extension of ${\mathcal M}$. Let ${\mathfrak X}$ be the set of subsets of M that are coded by ${\mathcal N}$. Then ${\mathcal M}$ has a…

Logic · Mathematics 2016-09-09 James H. Schmerl

We show that supercompactness and strong compactness can be equivalent even as properties of pairs of regular cardinals. Specifically, we show that if V models ZFC + GCH is a given model (which in interesting cases contains instances of…

Logic · Mathematics 2016-09-06 Arthur Apter , Saharon Shelah

Let $ K / k $ be a purely inseparable extension of characteristic $ p> 0 $ and of finite size. We recall that $K/k$ is modular if for every $n \in \mathbb{N}$,$K^{p^n}$ and $k$ are $k\cap K^{p^ n}$-linearly disjoint. A natural…

Commutative Algebra · Mathematics 2017-07-18 Hassane Fliouet

A classical theorem of Hechler asserts that the structure $\left(\omega^\omega,\le^*\right)$ is universal in the sense that for any $\sigma$-directed poset P with no maximal element, there is a ccc forcing extension in which…

Logic · Mathematics 2020-04-21 Gabriel Fernandes , Miguel Moreno , Assaf Rinot

Our main result in this article is a compactness result which states that a noncollapsed sequence of asymptotically locally Euclidean (ALE) scalar-flat K\"ahler metrics on a minimal K\"ahler surface whose K\"ahler classes stay in a compact…

Differential Geometry · Mathematics 2020-02-19 Jiyuan Han , Jeff A. Viaclovsky

An inner model M is MINIMAL if there is a class A such that <M,A> is amenable yet has no transitive proper elementary submodel. We study minimal universes in the context of 0#. For example we prove: If 0# exists then there is an inner model…

Logic · Mathematics 2008-02-03 Sy D. Friedman

Let P be a distinguished unary predicate and K= {M: M a model of cardinality aleph_n with P^M of cardinality aleph_0}. We prove that consistently for n=4, for some countable first order theory T we have: T has no model in K whereas every…

Logic · Mathematics 2007-05-23 Saharon Shelah

We prove that if continuum is not a Kunen cardinal, then there is a uniform Eberlein compact space $K$ such that the Banach space $C(K)$ does not embed isometrically into $\ell_\infty/c_0$. We prove a similar result for isomorphic…

Functional Analysis · Mathematics 2018-12-12 Mikolaj Krupski , Witold Marciszewski

We isolate a new large cardinal concept, "remarkability." Consistencywise, remarkable cardinals are between ineffable and omega-Erdos cardinals. They are characterized by the existence of "0^sharp-like" embeddings; however, they relativize…

Logic · Mathematics 2007-05-23 Ralf Schindler

If an extension Vbar of V satisfies the delta approximation and cover properties for classes and V is a class in Vbar, then every suitably closed embedding j:Vbar to Nbar in Vbar with critical point above delta restricts to an embedding…

Logic · Mathematics 2014-11-18 Joel David Hamkins

This paper contains portions of Baldwin's talk at the Set Theory and Model Theory Conference (Institute for Research in Fundamental Sciences, Tehran, October 2015) and a detailed proof that in a suitable extension of ZFC, there is a…

Logic · Mathematics 2021-11-03 John T. Baldwin , Saharon Shelah