6 found
  1.  28
    The 116 Reducts of (ℚ, <,A).Markus Junker & Martin Ziegler - 2008 - Journal of Symbolic Logic 73 (3):861-884.
    This article aims to classify those reducts of expansions of (Q, <) by unary predicates which eliminate quantifiers, and in particular to show that, up to interdefinability, there are only finitely many for a given language. Equivalently, we wish to classify the closed subgroups of Sym(Q) containing the group of all automorphisms of (Q, <) fixing setwise certain subsets. This goal is achieved for expansions by convex predicates, yielding expansions by constants as a special case, and for the expansion by (...)
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  2.  26
    A Note on Equational Theories.Markus Junker - 2000 - Journal of Symbolic Logic 65 (4):1705-1712.
  3.  14
    The Indiscernible Topology: A Mock Zariski Topology.Markus Junker & Daniel Lascar - 2001 - Journal of Mathematical Logic 1 (01):99-124.
    We associate with every first order structure [Formula: see text] a family of invariant, locally Noetherian topologies. The structure is almost determined by the topologies, and properties of the structure are reflected by topological properties. We study these topologies in particular for stable structures. In nice cases, we get a behaviour similar to the Zariski topology in algebraically closed fields.
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  4.  37
    On Bellissima’s Construction of the Finitely Generated Free Heyting Algebras, and Beyond.Luck Darnière & Markus Junker - 2010 - Archive for Mathematical Logic 49 (7-8):743-771.
    We study finitely generated free Heyting algebras from a topological and from a model theoretic point of view. We review Bellissima’s representation of the finitely generated free Heyting algebra; we prove that it yields an embedding in the profinite completion, which is also the completion with respect to a naturally defined metric. We give an algebraic interpretation of the Kripke model used by Bellissima as the principal ideal spectrum and show it to be first order interpretable in the Heyting algebra, (...)
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  5.  17
    Theories with Equational Forking.Markus Junker & Ingo Kraus - 2002 - Journal of Symbolic Logic 67 (1):326-340.
    We show that equational independence in the sense of Srour equals local non-forking. We then examine so-called almost equational theories where equational independence is a symmetric relation.
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  6.  17
    Schlanke Körper (Slim fields).Markus Junker & Jochen Koenigsmann - 2010 - Journal of Symbolic Logic 75 (2):481-500.
    We examine fields in which model theoretic algebraic closure coincides with relative field theoretic algebraic closure. These are perfect fields with nice model theoretic behaviour. For example, they are exactly the fields in which algebraic independence is an abstract independence relation in the sense of Kim and Pillay. Classes of examples are perfect PAC fields, model complete large fields and henselian valued fields of characteristic 0.
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