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  1.  1
    Homomorphism Reductions on Polish Groups.Konstantinos A. Beros - 2018 - Archive for Mathematical Logic 57 (7-8):795-807.
    In an earlier paper, we introduced the following pre-order on the subgroups of a given Polish group: if G is a Polish group and \ are subgroups, we say H is homomorphism reducible to L iff there is a continuous group homomorphism \ such that \\). We previously showed that there is a \ subgroup L of the countable power of any locally compact Polish group G such that every \ subgroup of \ is homomorphism reducible to L. In the (...)
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  2.  3
    Embedding Locales and Formal Topologies Into Positive Topologies.Francesco Ciraulo & Giovanni Sambin - 2018 - Archive for Mathematical Logic 57 (7-8):755-768.
    A positive topology is a set equipped with two particular relations between elements and subsets of that set: a convergent cover relation and a positivity relation. A set equipped with a convergent cover relation is a predicative counterpart of a locale, where the given set plays the role of a set of generators, typically a base, and the cover encodes the relations between generators. A positivity relation enriches the structure of a locale; among other things, it is a tool to (...)
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  3.  4
    Generic Variations and NTP$$_$$.Jan Dobrowolski - 2018 - Archive for Mathematical Logic 57 (7-8):861-871.
    We prove a preservation theorem for NTP\ in the context of the generic variations construction. We also prove that NTP\ is preserved under adding to a geometric theory a generic predicate.
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  4. Generic Variations and NTP$$_1$$1.Jan Dobrowolski - 2018 - Archive for Mathematical Logic 57 (7-8):861-871.
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  5.  2
    Closure Properties of Parametric Subcompleteness.Gunter Fuchs - 2018 - Archive for Mathematical Logic 57 (7-8):829-852.
    For an ordinal \, I introduce a variant of the notion of subcompleteness of a forcing poset, which I call \-subcompleteness, and show that this class of forcings enjoys some closure properties that the original class of subcomplete forcings does not seem to have: factors of \-subcomplete forcings are \-subcomplete, and if \ and \ are forcing-equivalent notions, then \ is \-subcomplete iff \ is. I formulate a Two Step Theorem for \-subcompleteness and prove an RCS iteration theorem for \-subcompleteness (...)
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  6.  8
    Hanf Number for Scott Sentences of Computable Structures.S. S. Goncharov, J. F. Knight & I. Souldatos - 2018 - Archive for Mathematical Logic 57 (7-8):889-907.
    The Hanf number for a set S of sentences in \ is the least infinite cardinal \ such that for all \, if \ has models in all infinite cardinalities less than \, then it has models of all infinite cardinalities. Friedman asked what is the Hanf number for Scott sentences of computable structures. We show that the value is \. The same argument proves that \ is the Hanf number for Scott sentences of hyperarithmetical structures.
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  7.  6
    Consistency of the Intensional Level of the Minimalist Foundation with Church’s Thesis and Axiom of Choice.Hajime Ishihara, Maria Emilia Maietti, Samuele Maschio & Thomas Streicher - 2018 - Archive for Mathematical Logic 57 (7-8):873-888.
    Consistency with the formal Church’s thesis, for short CT, and the axiom of choice, for short AC, was one of the requirements asked to be satisfied by the intensional level of a two-level foundation for constructive mathematics as proposed by Maietti and Sambin From sets and types to topology and analysis: practicable foundations for constructive mathematics, Oxford University Press, Oxford, 2005). Here we show that this is the case for the intensional level of the two-level Minimalist Foundation, for short MF, (...)
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  8.  1
    Model Completeness of Generic Graphs in Rational Cases.Hirotaka Kikyo - 2018 - Archive for Mathematical Logic 57 (7-8):769-794.
    Let \ be an ab initio amalgamation class with an unbounded increasing concave function f. We show that if the predimension function has a rational coefficient and f satisfies a certain assumption then the generic structure of \ has a model complete theory.
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  9.  3
    On Partial Disjunction Properties of Theories Containing Peano Arithmetic.Taishi Kurahashi - 2018 - Archive for Mathematical Logic 57 (7-8):953-980.
    Let \ be a class of formulas. We say that a theory T in classical logic has the \-disjunction property if for any \ sentences \ and \, either \ or \ whenever \. First, we characterize the \-disjunction property in terms of the notion of partial conservativity. Secondly, we prove a model theoretic characterization result for \-disjunction property. Thirdly, we investigate relationships between partial disjunction properties and several other properties of theories containing Peano arithmetic. Finally, we investigate unprovability of (...)
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  10.  2
    A Model of $$Mathsf {ZFA}+ Mathsf {PAC}$$ with No Outer Model of $$Mathsf {ZFAC}$$ZFAC with the Same Pure Part.Paul Larson & Saharon Shelah - 2018 - Archive for Mathematical Logic 57 (7-8):853-859.
    We produce a model of \ such that no outer model of \ has the same pure sets, answering a question asked privately by Eric Hall.
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  11. A Model of $$\Mathsf {ZFA}+ \Mathsf {PAC}$$ZFA+PAC with No Outer Model of $$\Mathsf {ZFAC}$$ZFAC with the Same Pure Part.Paul Larson & Saharon Shelah - 2018 - Archive for Mathematical Logic 57 (7-8):853-859.
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  12.  2
    Stationary Sets Added When Forcing Squares.Maxwell Levine - 2018 - Archive for Mathematical Logic 57 (7-8):909-916.
    Current research in set theory raises the possibility that \ can be made compatible with some stationary reflection, depending on the parameter \. The purpose of this paper is to demonstrate the difficulty in such results. We prove that the poset \\), which adds a \-sequence by initial segments, will also add non-reflecting stationary sets concentrating in any given cofinality below \. We also investigate the CMB poset, which adds \ in a slightly different way. We prove that the CMB (...)
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  13.  3
    Splitting Idempotents in a Fibered Setting.Ruggero Pagnan - 2018 - Archive for Mathematical Logic 57 (7-8):917-938.
    By splitting idempotent morphisms in the total and base categories of fibrations we provide an explicit elementary description of the Cauchy completion of objects in the categories Fib) of fibrations with a fixed base category \ and Fib of fibrations with any base category. Two universal constructions are at issue, corresponding to two fibered reflections involving the fibration of fibrations \.
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  14.  11
    A Partition Relation for Pairs on $$Omega ^{Omega ^Omega }$$.Claribet Piña - 2018 - Archive for Mathematical Logic 57 (7-8):727-753.
    We consider colorings of the pairs of a family \ of topological type \, for \; and we find a homogeneous family \ for each coloring. As a consequence, we complete our study of the partition relation \^2_{l,m}}\) identifying \ as the smallest ordinal space \^2_{l,4}}\).
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  15.  2
    Definability of Types and VC Density in Differential Topological Fields.Françoise Point - 2018 - Archive for Mathematical Logic 57 (7-8):809-828.
    Given a model-complete theory of topological fields, we considered its generic differential expansions and under a certain hypothesis of largeness, we axiomatised the class of existentially closed ones. Here we show that a density result for definable types over definably closed subsets in such differential topological fields. Then we show two transfer results, one on the VC-density and the other one, on the combinatorial property NTP2.
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  16. A Collection of Topological Ramsey Spaces of Trees and Their Application to Profinite Graph Theory.Yuan Yuan Zheng - 2018 - Archive for Mathematical Logic 57 (7-8):939-952.
    We construct a collection of new topological Ramsey spaces of trees. It is based on the Halpern-Läuchli theorem, but different from the Milliken space of strong subtrees. We give an example of its application by proving a partition theorem for profinite graphs.
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  17.  4
    Derivatives of Normal Functions and $$\Omega $$ Ω -Models.Toshiyasu Arai - 2018 - Archive for Mathematical Logic 57 (5-6):649-664.
    In this note the well-ordering principle for the derivative \ of normal functions \ on ordinals is shown to be equivalent to the existence of arbitrarily large countable coded \-models of the well-ordering principle for the function \.
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  18.  1
    Ax–Schanuel for Linear Differential Equations.Vahagn Aslanyan - 2018 - Archive for Mathematical Logic 57 (5-6):629-648.
    We generalise the exponential Ax–Schanuel theorem to arbitrary linear differential equations with constant coefficients. Using the analysis of the exponential differential equation by Kirby :445–486, 2009) and Crampin we give a complete axiomatisation of the first order theories of linear differential equations and show that the generalised Ax–Schanuel inequalities are adequate for them.
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  19.  1
    Good Frames in the Hart–Shelah Example.Will Boney & Sebastien Vasey - 2018 - Archive for Mathematical Logic 57 (5-6):687-712.
    For a fixed natural number \, the Hart–Shelah example is an abstract elementary class with amalgamation that is categorical exactly in the infinite cardinals less than or equal to \. We investigate recently-isolated properties of AECs in the setting of this example. We isolate the exact amount of type-shortness holding in the example and show that it has a type-full good \-frame which fails the existence property for uniqueness triples. This gives the first example of such a frame. Along the (...)
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  20.  3
    Relative Exchangeability with Equivalence Relations.Harry Crane & Henry Towsner - 2018 - Archive for Mathematical Logic 57 (5-6):533-556.
    We describe an Aldous–Hoover-type characterization of random relational structures that are exchangeable relative to a fixed structure which may have various equivalence relations. Our main theorem gives the common generalization of the results on relative exchangeability due to Ackerman \)-invariant measures: part I, 2015. arXiv:1509.06170) and Crane and Towsner and hierarchical exchangeability results due to Austin and Panchenko :809–823, 2014).
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  21.  3
    Iterated Ultrapowers for the Masses.Ali Enayat, Matt Kaufmann & Zachiri McKenzie - 2018 - Archive for Mathematical Logic 57 (5-6):557-576.
    We present a novel, perspicuous framework for building iterated ultrapowers. Furthermore, our framework naturally lends itself to the construction of a certain type of order indiscernibles, here dubbed tight indiscernibles, which are shown to provide smooth proofs of several results in general model theory.
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  22.  4
    Bounding Quantification in Parametric Expansions of Presburger Arithmetic.John Goodrick - 2018 - Archive for Mathematical Logic 57 (5-6):577-591.
    Generalizing Cooper’s method of quantifier elimination for Presburger arithmetic, we give a new proof that all parametric Presburger families \ [as defined by Woods ] are definable by formulas with polynomially bounded quantifiers in an expanded language with predicates for divisibility by f for every polynomial \. In fact, this quantifier bounding method works more generally in expansions of Presburger arithmetic by multiplication by scalars \: \alpha \in R, t \in X\}\) where R is any ring of functions from X (...)
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  23.  1
    A Weird Relation Between Two Cardinals.Lorenz Halbeisen - 2018 - Archive for Mathematical Logic 57 (5-6):593-599.
    For a set M, let \\) denote the set of all finite sequences which can be formed with elements of M, and let \ denote the set of all 2-element subsets of M. Furthermore, for a set A, let Open image in new window denote the cardinality of A. It will be shown that the following statement is consistent with Zermelo–Fraenkel Set Theory \: There exists a set M such that Open image in new window and no function Open image (...)
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  24. Computable Valued Fields.Matthew Harrison-Trainor - 2018 - Archive for Mathematical Logic 57 (5-6):473-495.
    We investigate the computability-theoretic properties of valued fields, and in particular algebraically closed valued fields and p-adically closed valued fields. We give an effectiveness condition, related to Hensel’s lemma, on a valued field which is necessary and sufficient to extend the valuation to any algebraic extension. We show that there is a computable formally p-adic field which does not embed into any computable p-adic closure, but we give an effectiveness condition on the divisibility relation in the value group which is (...)
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  25.  3
    On a Class of Maximality Principles.Daisuke Ikegami & Nam Trang - 2018 - Archive for Mathematical Logic 57 (5-6):713-725.
    We study various classes of maximality principles, \\), introduced by Hamkins :527–550, 2003), where \ defines a class of forcing posets and \ is an infinite cardinal. We explore the consistency strength and the relationship of \\) with various forcing axioms when \. In particular, we give a characterization of bounded forcing axioms for a class of forcings \ in terms of maximality principles MP\\) for \ formulas. A significant part of the paper is devoted to studying the principle MP\\) (...)
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  26.  15
    Shadows of the Axiom of Choice in the Universe $$L$$.Jan Mycielski & Grzegorz Tomkowicz - 2018 - Archive for Mathematical Logic 57 (5-6):607-616.
    We show that several theorems about Polish spaces, which depend on the axiom of choice ), have interesting corollaries that are theorems of the theory \, where \ is the axiom of dependent choices. Surprisingly it is natural to use the full \ to prove the existence of these proofs; in fact we do not even know the proofs in \. Let \ denote the axiom of determinacy. We show also, in the theory \\), a theorem which strenghtens and generalizes (...)
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  27.  8
    Borel Globalizations of Partial Actions of Polish Groups.H. Pinedo & C. Uzcategui - 2018 - Archive for Mathematical Logic 57 (5-6):617-627.
    We show that the enveloping space \ of a partial action of a Polish group G on a Polish space \ is a standard Borel space, that is to say, there is a topology \ on \ such that \\) is Polish and the quotient Borel structure on \ is equal to \\). To prove this result we show a generalization of a theorem of Burgess about Borel selectors for the orbit equivalence relation induced by a group action and also (...)
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  28. On the Minimal Cover Property and Certain Notions of Finite.Eleftherios Tachtsis - 2018 - Archive for Mathematical Logic 57 (5-6):665-686.
    In set theory without the axiom of choice, we investigate the deductive strength of the principle “every topological space with the minimal cover property is compact”, and its relationship with certain notions of finite as well as with properties of linearly ordered sets and partially ordered sets.
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  29.  1
    Complete Groups Are Complete Co-Analytic.Simon Thomas - 2018 - Archive for Mathematical Logic 57 (5-6):601-606.
    The set of complete groups is a complete co-analytic subset of the standard Borel space of countably infinite groups.
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  30.  1
    Epsilon Substitution for $$Textit{ID}_1$$ Via Cut-Elimination.Henry Towsner - 2018 - Archive for Mathematical Logic 57 (5-6):497-531.
    The \-substitution method is a technique for giving consistency proofs for theories of arithmetic. We use this technique to give a proof of the consistency of the impredicative theory \ using a variant of the cut-elimination formalism introduced by Mints.
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  31.  2
    Epsilon Substitution for $$\Textit{ID}_1$$ ID 1 Via Cut-Elimination.Henry Towsner - 2018 - Archive for Mathematical Logic 57 (5-6):497-531.
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  32.  6
    Maximal Trees.Jörg Brendle - 2018 - Archive for Mathematical Logic 57 (3-4):421-428.
    We show that, consistently, there can be maximal subtrees of \\) and \ / {\mathrm {fin}}\) of arbitrary regular uncountable size below the size of the continuum \. We also show that there are no maximal subtrees of \ / {\mathrm {fin}}\) with countable levels. Our results answer several questions of Campero-Arena et al..
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  33.  2
    Some Remarks on Baire’s Grand Theorem.Riccardo Camerlo & Jacques Duparc - 2018 - Archive for Mathematical Logic 57 (3-4):195-201.
    We provide a game theoretical proof of the fact that if f is a function from a zero-dimensional Polish space to \ that has a point of continuity when restricted to any non-empty compact subset, then f is of Baire class 1. We use this property of the restrictions to compact sets to give a generalisation of Baire’s grand theorem for functions of any Baire class.
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  34.  2
    A Weak Variant of Hindman’s Theorem Stronger Than Hilbert’s Theorem.Lorenzo Carlucci - 2018 - Archive for Mathematical Logic 57 (3-4):381-389.
    Hirst investigated a natural restriction of Hindman’s Finite Sums Theorem—called Hilbert’s Theorem—and proved it equivalent over \ to the Infinite Pigeonhole Principle for all colors. This gave the first example of a natural restriction of Hindman’s Theorem provably much weaker than Hindman’s Theorem itself. We here introduce another natural restriction of Hindman’s Theorem—which we name the Adjacent Hindman’s Theorem with apartness—and prove it to be provable from Ramsey’s Theorem for pairs and strictly stronger than Hirst’s Hilbert’s Theorem. The lower bound (...)
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  35.  3
    Implicational Logics III: Completeness Properties.Petr Cintula & Carles Noguera - 2018 - Archive for Mathematical Logic 57 (3-4):391-420.
    This paper presents an abstract study of completeness properties of non-classical logics with respect to matricial semantics. Given a class of reduced matrix models we define three completeness properties of increasing strength and characterize them in several useful ways. Some of these characterizations hold in absolute generality and others are for logics with generalized implication or disjunction connectives, as considered in the previous papers. Finally, we consider completeness with respect to matrices with a linear dense order and characterize it in (...)
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  36.  4
    The Subcompleteness of Magidor Forcing.Gunter Fuchs - 2018 - Archive for Mathematical Logic 57 (3-4):273-284.
    It is shown that the Magidor forcing to collapse the cofinality of a measurable cardinal that carries a length \ sequence of normal ultrafilters, increasing in the Mitchell order, to \, is subcomplete.
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  37.  2
    Interpretable Groups in Mann Pairs.Haydar Göral - 2018 - Archive for Mathematical Logic 57 (3-4):203-237.
    In this paper, we study an algebraically closed field \ expanded by two unary predicates denoting an algebraically closed proper subfield k and a multiplicative subgroup \. This will be a proper expansion of algebraically closed field with a group satisfying the Mann property, and also pairs of algebraically closed fields. We first characterize the independence in the triple \\). This enables us to characterize the interpretable groups when \ is divisible. Every interpretable group H in \\) is, up to (...)
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  38.  3
    Countable OD Sets of Reals Belong to the Ground Model.Vladimir Kanovei & Vassily Lyubetsky - 2018 - Archive for Mathematical Logic 57 (3-4):285-298.
    It is true in the Cohen, Solovay-random, dominaning, and Sacks generic extension, that every countable ordinal-definable set of reals belongs to the ground universe. It is true in the Solovay collapse model that every non-empty OD countable set of sets of reals consists of \ elements.
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  39.  3
    Scott Sentences for Certain Groups.Julia F. Knight & Vikram Saraph - 2018 - Archive for Mathematical Logic 57 (3-4):453-472.
    We give Scott sentences for certain computable groups, and we use index set calculations as a way of checking that our Scott sentences are as simple as possible. We consider finitely generated groups and torsion-free abelian groups of finite rank. For both kinds of groups, the computable ones all have computable \ Scott sentences. Sometimes we can do better. In fact, the computable finitely generated groups that we have studied all have Scott sentences that are “computable d-\” sentence and a (...)
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  40.  3
    Decidability of the AE-Theory of the Lattice of $${\varPi }_1^0$$ Π 1 0 Classes.Linda Lawton - 2018 - Archive for Mathematical Logic 57 (3-4):429-451.
    An AE-sentence is a sentence in prenex normal form with all universal quantifiers preceding all existential quantifiers, and the AE-theory of a structure is the set of all AE-sentences true in the structure. We show that the AE-theory of \, \cap, \cup, 0, 1)\) is decidable by giving a procedure which, for any AE-sentence in the language, determines the truth or falsity of the sentence in our structure.
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  41.  3
    Expressivity in Chain-Based Modal Logics.Michel Marti & George Metcalfe - 2018 - Archive for Mathematical Logic 57 (3-4):361-380.
    We investigate the expressivity of many-valued modal logics based on an algebraic structure with a complete linearly ordered lattice reduct. Necessary and sufficient algebraic conditions for admitting a suitable Hennessy–Milner property are established for classes of image-finite and modally saturated models. Full characterizations are obtained for many-valued modal logics based on complete BL-chains that are finite or have the real unit interval [0, 1] as a lattice reduct, including Łukasiewicz, Gödel, and product modal logics.
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  42.  3
    On Katětov and Katětov–Blass Orders on Analytic P-Ideals and Borel Ideals.Hiroshi Sakai - 2018 - Archive for Mathematical Logic 57 (3-4):317-327.
    Minami–Sakai :883–898, 2016) investigated the cofinal types of the Katětov and the Katětov–Blass orders on the family of all \ ideals. In this paper we discuss these orders on analytic P-ideals and Borel ideals. We prove the following:The family of all analytic P-ideals has the largest element with respect to the Katětov and the Katětov–Blass orders.The family of all Borel ideals is countably upward directed with respect to the Katětov and the Katětov–Blass orders. In the course of the proof of (...)
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  43.  2
    Continuous Reducibility and Dimension of Metric Spaces.Philipp Schlicht - 2018 - Archive for Mathematical Logic 57 (3-4):329-359.
    If is a Polish metric space of dimension 0, then by Wadge’s lemma, no more than two Borel subsets of X are incomparable with respect to continuous reducibility. In contrast, our main result shows that for any metric space of positive dimension, there are uncountably many Borel subsets of that are pairwise incomparable with respect to continuous reducibility. In general, the reducibility that is given by the collection of continuous functions on a topological space \\) is called the Wadge quasi-order (...)
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  44.  1
    L -Groups C in Continuous Logic.Philip Scowcroft - 2018 - Archive for Mathematical Logic 57 (3-4):239-272.
    In the context of continuous logic, this paper axiomatizes both the class \ of lattice-ordered groups isomorphic to C for X compact and the subclass \ of structures existentially closed in \; shows that the theory of \ is \-categorical and admits elimination of quantifiers; establishes a Nullstellensatz for \ and \; shows that \\in \mathcal {C}\) has a prime-model extension in \ just in case X is Boolean; and proves that in a sense relevant to continuous logic, positive formulas (...)
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  45.  2
    Quasiminimal Abstract Elementary Classes.Sebastien Vasey - 2018 - Archive for Mathematical Logic 57 (3-4):299-315.
    We propose the notion of a quasiminimal abstract elementary class. This is an AEC satisfying four semantic conditions: countable Löwenheim–Skolem–Tarski number, existence of a prime model, closure under intersections, and uniqueness of the generic orbital type over every countable model. We exhibit a correspondence between Zilber’s quasiminimal pregeometry classes and quasiminimal AECs: any quasiminimal pregeometry class induces a quasiminimal AEC, and for any quasiminimal AEC there is a natural functorial expansion that induces a quasiminimal pregeometry class. We show in particular (...)
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  46.  4
    Aronszajn and Kurepa Trees.James Cummings - 2018 - Archive for Mathematical Logic 57 (1-2):83-90.
    Monroe Eskew and \, 2016. https://mathoverflow.net/questions/217951/tree-properties-on-omega-1-and-omega-2) asked whether the tree property at \ implies there is no Kurepa tree. We prove that the tree property at \ is consistent with the existence of \-trees with as many branches as desired.
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  47.  2
    Largest Initial Segments Pointwise Fixed by Automorphisms of Models of Set Theory.Ali Enayat, Matt Kaufmann & Zachiri McKenzie - 2018 - Archive for Mathematical Logic 57 (1-2):91-139.
    Given a model \ of set theory, and a nontrivial automorphism j of \, let \\) be the submodel of \ whose universe consists of elements m of \ such that \=x\) for every x in the transitive closure of m ). Here we study the class \ of structures of the form \\), where the ambient model \ satisfies a frugal yet robust fragment of \ known as \, and \=m\) whenever m is a finite ordinal in the sense (...)
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  48.  3
    Preface.Ali Enayat, Massoud Pourmahdian & Ralf Schindler - 2018 - Archive for Mathematical Logic 57 (1-2):1-2.
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  49.  2
    The Small Index Property for Homogeneous Models in AEC's.Zaniar Ghadernezhad & Andrés Villaveces - 2018 - Archive for Mathematical Logic 57 (1-2):141-157.
    We prove a version of a small index property theorem for strong amalgamation classes. Our result builds on an earlier theorem by Lascar and Shelah. We then study versions of the small index property for various non-elementary classes. In particular, we obtain the small index property for quasiminimal pregeometry structures.
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  50.  6
    The Tree Property at the Successor of a Singular Limit of Measurable Cardinals.Mohammad Golshani - 2018 - Archive for Mathematical Logic 57 (1-2):3-25.
    Assume \ is a singular limit of \ supercompact cardinals, where \ is a limit ordinal. We present two methods for arranging the tree property to hold at \ while making \ the successor of the limit of the first \ measurable cardinals. The first method is then used to get, from the same assumptions, the tree property at \ with the failure of SCH at \. This extends results of Neeman and Sinapova. The second method is also used to (...)
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  51.  2
    On a Question of Silver About Gap-Two Cardinal Transfer Principles.Mohammad Golshani & Shahram Mohsenipour - 2018 - Archive for Mathematical Logic 57 (1-2):27-35.
    Assuming the existence of a Mahlo cardinal, we produce a generic extension of Gödel’s constructible universe L, in which the \ holds and the transfer principles \ \rightarrow \) and \ \rightarrow \) fail simultaneously. The result answers a question of Silver from 1971. We also extend our result to higher gaps.
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  52.  3
    Model Theory of Finite and Pseudofinite Groups.Dugald Macpherson - 2018 - Archive for Mathematical Logic 57 (1-2):159-184.
    This is a survey, intended both for group theorists and model theorists, concerning the structure of pseudofinite groups, that is, infinite models of the first-order theory of finite groups. The focus is on concepts from stability theory and generalisations in the context of pseudofinite groups, and on the information this might provide for finite group theory.
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  53.  4
    On Some Dynamical Aspects of NIP Theories.Alireza Mofidi - 2018 - Archive for Mathematical Logic 57 (1-2):37-71.
    We investigate some dynamical features of the actions of automorphisms in the context of model theory. We interpret a few notions such as compact systems, entropy and symbolic representations from the theory of dynamical systems in the realm of model theory. In this direction, we settle a number of characterizations of NIP theories in terms of dynamics of automorphisms and invariant measures. For example, it is shown that the property of NIP corresponds to the compactness property of some associated systems (...)
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  54.  3
    The Long Extender Algebra.Ralf Schindler - 2018 - Archive for Mathematical Logic 57 (1-2):73-82.
    Generalizing Woodin’s extender algebra, cf. e.g. Steel Handbook of set theory, Springer, Berlin, 2010), we isolate the long extender algebra as a general version of Bukowský’s forcing, cf. Bukovský, in the presence of a supercompact cardinal.
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  55.  6
    Collapsing $$Omega _2$$ with Semi-Proper Forcing.Stevo Todorcevic - 2018 - Archive for Mathematical Logic 57 (1-2):185-194.
    We examine the differences between three standard classes of forcing notions relative to the way they collapse the continuum. It turns out that proper and semi-proper posets behave differently in that respect from the class of posets that preserve stationary subsets of \.
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