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  1. Ludomir Newelski (2009). Topological Dynamics of Definable Group Actions. Journal of Symbolic Logic 74 (1):50-72.
    We interpret the basic notions of topological dynamics in the model-theoretic setting, relating them to generic types of definable group actions and their generalizations.
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  2. Jakub Gismatullin & Ludomir Newelski (2008). G-Compactness and Groups. Archive for Mathematical Logic 47 (5):479-501.
    Lascar described E KP as a composition of E L and the topological closure of E L (Casanovas et al. in J Math Log 1(2):305–319). We generalize this result to some other pairs of equivalence relations. Motivated by an attempt to construct a new example of a non-G-compact theory, we consider the following example. Assume G is a group definable in a structure M. We define a structure M′ consisting of M and X as two sorts, where X is an (...)
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  3. Ludomir Newelski (2007). Relative Vaught's Conjecture for Some Meager Groups. Notre Dame Journal of Formal Logic 48 (1):115-132.
    Assume G is a superstable locally modular group. We describe for any countable model M of Th(G) the quotient group G(M) / Gm(M). Here Gm is the modular part of G. Also, under some additional assumptions we describe G(M) / Gm(M) relative to G⁻(M). We prove Vaught's Conjecture for Th(G) relative to Gm and a finite set provided that ℳ(G) = 1 and the ring of pseudoendomorphisms of G is finite.
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  4. Ludomir Newelski (2003). Very Simple Theories Without Forking. Archive for Mathematical Logic 42 (6):601-616.
    We prove Vaught's conjecture for minimal trivial simple theories satisfying the generalized independence theorem.
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  5. Ludomir Newelski (2002). Modular Types in Some Supersimple Theories. Journal of Symbolic Logic 67 (4):1601-1615.
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  6. Ludomir Newelski & Krzysztof Krupi?Ski (2002). On Bounded Type-Definable Equivalence Relations. Notre Dame Journal of Formal Logic 43 (4):231-242.
    We investigate some topological properties of the spaces of classes of bounded type-definable equivalence relations.
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  7. Ludomir Newelski (2001). Small Profinite Groups. Journal of Symbolic Logic 66 (2):859-872.
    We propose a model-theoretic framework for investigating profinite groups. Within this framework we define and investigate small profinite groups. We consider the question if any small profinite group has an open abelian subgroup.
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  8. Ludomir Newelski & Roman Wencel (2001). Definable Sets in Boolean-Ordered o-Minimal Structures. I. Journal of Symbolic Logic 66 (4):1821-1836.
    We prove weak elimination of imaginary elements for Boolean orderings with finitely many atoms. As a consequence we obtain equivalence of the two notions of o-minimality for Boolean ordered structures, introduced by C. Toffalori. We investigate atoms in Boolean algebras induced by algebraically closed subsets of Boolean ordered structures. We prove uniqueness of prime models in strongly o-minimal theories of Boolean ordered structures.
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  9. Ludomir Newelski (1999). Flat Morley Sequences. Journal of Symbolic Logic 64 (3):1261-1279.
    Assume T is a small superstable theory. We introduce the notion of a flat Morley sequence, which is a counterpart of the notion of an infinite Morley sequence in a type p, in case when p is a complete type over a finite set of parameters. We show that for any flat Morley sequence Q there is a model M of T which is τ-atomic over {Q}. When additionally T has few countable models and is 1-based, we prove that within (...)
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  10. Ludomir Newelski (1999). Geometry of *-Finite Types. Journal of Symbolic Logic 64 (4):1375-1395.
    Assume T is a superstable theory with $ countable models. We prove that any *-algebraic type of M-rank > 0 is m-nonorthogonal to a *-algebraic type of M-rank 1. We study the geometry induced by m-dependence on a *-algebraic type p* of M-rank 1. We prove that after some localization this geometry becomes projective over a division ring F. Associated with p* is a meager type p. We prove that p is determined by p* up to nonorthogonality and that F (...)
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  11. Ludomir Newelski (1996). On Atomic or Saturated Sets. Journal of Symbolic Logic 61 (1):318-333.
    Assume T is stable, small and Φ(x) is a formula of L(T). We study the impact on $T\lceil\Phi$ of naming finitely many elements of a model of T. We consider the cases of $T\lceil\Phi$ which is ω-stable or superstable of finite rank. In these cases we prove that if T has $ countable models and Q = Φ(M) is countable and atomic or saturated, then any good type in S(Q) is τ-stable. If $T\lceil\Phi$ is ω-stable and (bounded, 1-based or of (...)
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  12. Ludomir Newelski (1995). A Model and its Subset: The Uncountable Case. Annals of Pure and Applied Logic 71 (2):107-129.
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  13. Ludomir Newelski (1994). Meager Forking. Annals of Pure and Applied Logic 70 (2):141-175.
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  14. Ludomir Newelski (1993). Scott Analysis of Pseudotypes. Journal of Symbolic Logic 58 (2):648-663.
    This is a continuation of [N2]. We find a Borel definition of Q-isolation. We pursue a topological and Scott analysis of pseudotypes on S(Q).
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  15. Ludomir Newelski (1992). A Model and its Subset. Journal of Symbolic Logic 57 (2):644-658.
    We try to count the number of countable models M of T with a fixed set Q = φ (M) of realizations of a type φ. Also, for stable T, we define an ordinal rank M measuring multiplicity of types, with additivity properties similar to those of U-rank.
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  16. Ludomir Newelski (1990). Omitting Types for Stable CCC Theories. Journal of Symbolic Logic 55 (3):1037-1047.
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  17. Ludomir Newelski (1990). Weakly Minimal Formulas: A Global Approach. Annals of Pure and Applied Logic 46 (1):65-94.
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  18. Ludomir Newelski (1987). On Partitions of the Real Line Into Compact Sets. Journal of Symbolic Logic 52 (2):353-359.
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  19. Ludomir Newelski (1987). Omitting Types and the Real Line. Journal of Symbolic Logic 52 (4):1020-1026.
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