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  1.  7
    Nonstandard Models in Recursion Theory and Reverse Mathematics.C. T. Chong, Wei Li & Yue Yang - 2014 - Bulletin of Symbolic Logic 20 (2):170-200.
  2.  8
    Computable Categoricity and the Ershov Hierarchy.Bakhadyr Khoussainov, Frank Stephan & Yue Yang - 2008 - Annals of Pure and Applied Logic 156 (1):86-95.
    In this paper, the notions of Fα-categorical and Gα-categorical structures are introduced by choosing the isomorphism such that the function itself or its graph sits on the α-th level of the Ershov hierarchy, respectively. Separations obtained by natural graphs which are the disjoint unions of countably many finite graphs. Furthermore, for size-bounded graphs, an easy criterion is given to say when it is computable-categorical and when it is only G2-categorical; in the latter case it is not Fα-categorical for any recursive (...)
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  3.  29
    On the Definable Ideal Generated by Nonbounding C.E. Degrees.Liang Yu & Yue Yang - 2005 - Journal of Symbolic Logic 70 (1):252 - 270.
    Let [NB]₁ denote the ideal generated by nonbounding c.e. degrees and NCup the ideal of noncuppable c.e. degrees. We show that both [NB]₁ ∪ NCup and the ideal generated by nonbounding and noncuppable degrees are new, in the sense that they are different from M, [NB]₁ and NCup—the only three known definable ideals so far.
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  4.  7
    The Members of Thin and Minimal Π 1 0 Classes, Their Ranks and Turing Degrees.Rodney G. Downey, Guohua Wu & Yue Yang - 2015 - Annals of Pure and Applied Logic 166 (7-8):755-766.
  5.  19
    Properly Σ2 Minimal Degrees and 0″ Complementation.S. Barry Cooper, Andrew E. M. Lewis & Yue Yang - 2005 - Mathematical Logic Quarterly 51 (3):274-276.
    We show that there exists a properly Σ2 minimal degree b, and moreover that b can be chosen to join with 0′ to 0″ – so that b is a 0″ complement for every degree a such that 0′ ≤ a < 0″.
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  6.  28
    Bounding and Nonbounding Minimal Pairs in the Enumeration Degrees.S. Barry Cooper, Angsheng Li, Andrea Sorbi & Yue Yang - 2005 - Journal of Symbolic Logic 70 (3):741 - 766.
    We show that every nonzero $\Delta _{2}^{0}$ e-degree bounds a minimal pair. On the other hand, there exist $\Sigma _{2}^{0}$ e-degrees which bound no minimal pair.
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  7.  6
    Properly Σ2 Minimal Degrees and 0″ Complementation.S. Cooper, Andrew Lewis & Yue Yang - 2005 - Mathematical Logic Quarterly 51 (3):274-276.
    We show that there exists a properly Σ2 minimal degree b, and moreover that b can be chosen to join with 0′ to 0″ – so that b is a 0″ complement for every degree a such that 0′ ≤ a < 0″.
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  8.  9
    ∑2 Induction and Infinite Injury Priority Arguments, Part II Tame ∑2 Coding and the Jump Operator.C. T. Chong & Yue Yang - 1997 - Annals of Pure and Applied Logic 87 (2):103-116.
  9.  22
    Bounding Computably Enumerable Degrees in the Ershov Hierarchy.Angsheng Li, Guohua Wu & Yue Yang - 2006 - Annals of Pure and Applied Logic 141 (1):79-88.
    Lachlan observed that any nonzero d.c.e. degree bounds a nonzero c.e. degree. In this paper, we study the c.e. predecessors of d.c.e. degrees, and prove that given a nonzero d.c.e. degree , there is a c.e. degree below and a high d.c.e. degree such that bounds all the c.e. degrees below . This result gives a unified approach to some seemingly unrelated results. In particular, it has the following two known theorems as corollaries: there is a low c.e. degree isolating (...)
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  10.  28
    Σ2 Induction and Infinite Injury Priority Argument, Part I: Maximal Sets and the Jump Operator.C. T. Chong & Yue Yang - 1998 - Journal of Symbolic Logic 63 (3):797 - 814.
    Related Works: Part II: C. T. Chong, Yue Yang. $\Sigma_2$ Induction and Infinite Injury Priority Argument, Part II: Tame $\Sigma_2$ Coding and the Jump Operator. Ann. Pure Appl. Logic, vol. 87, no. 2, 103--116. Mathematical Reviews : MR1490049 Part III: C. T. Chong, Lei Qian, Theodore A. Slaman, Yue Yang. $\Sigma_2$ Induction and Infinite Injury Priority Argument, Part III: Prompt Sets, Minimal Paries and Shoenfield's Conjecture. Mathematical Reviews : MR1818378.
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  11.  6
    The Existence of High Nonbounding Degrees in the Difference Hierarchy.Chi Tat Chong, Angsheng Li & Yue Yang - 2006 - Annals of Pure and Applied Logic 138 (1):31-51.
    We study the jump hierarchy of d.c.e. Turing degrees and show that there exists a high d.c.e. degree d which does not bound any minimal pair of d.c.e. degrees.
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  12.  10
    Iterated Trees and Fragments of Arithmetic.Yue Yang - 1995 - Archive for Mathematical Logic 34 (2):97-112.
  13.  6
    Degrees Containing Members of Thin Π10 Classes Are Dense and Co-Dense.Rodney G. Downey, Guohua Wu & Yue Yang - 2018 - Journal of Mathematical Logic 18 (1):1850001.
    In [Countable thin Π10 classes, Ann. Pure Appl. Logic 59 79–139], Cenzer, Downey, Jockusch and Shore proved the density of degrees containing members of countable thin Π10 classes. In the same paper, Cenzer et al. also proved the existence of degrees containing no members of thin Π10 classes. We will prove in this paper that the c.e. degrees containing no members of thin Π10 classes are dense in the c.e. degrees. We will also prove that the c.e. degrees containing members (...)
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  14.  18
    On Σ₁-Structural Differences Among Finite Levels of the Ershov Hierarchy.Yue Yang & Liang Yu - 2006 - Journal of Symbolic Logic 71 (4):1223 - 1236.
    We show that the structure R of recursively enumerable degrees is not a Σ₁-elementary substructure of Dn, where Dn (n > 1) is the structure of n-r.e. degrees in the Ershov hierarchy.
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  15.  4
    Bounding and Nonbounding Minimal Pairs in the Enumeration Degrees.S. Barry Cooper, Angsheng Li, Andrea Sorbi & Yue Yang - 2005 - Journal of Symbolic Logic 70 (3):741-766.
    We show that every nonzero Δ⁰₂ e-degree bounds a minimal pair. On the other hand, there exist Σ⁰₂ e-degrees which bound no minimal pair.
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  16.  7
    Nonstandard Models in Recursion Theory and Reverse Mathematics.C. T. Chong, Wei Li & Yue Yang - forthcoming - Association for Symbolic Logic: The Bulletin of Symbolic Logic.
    We give a survey of the study of nonstandard models in recursion theory and reverse mathematics. We discuss the key notions and techniques in effective computability in nonstandard models. and their applications to problems concerning combinatorial principles in subsystems of second order arithmetic. Particular attention is given to principles related to Ramsey's Theorem for Pairs.
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  17.  12
    The Thickness Lemma From $P- + I\Sum_1 + \Urcorner B\Sum2$.Yue Yang - 1995 - Journal of Symbolic Logic 60 (2):505 - 511.
  18.  4
    The Thickness Lemma From P − + IΣ1 + ¬BΣ2.Yue Yang - 1995 - Journal of Symbolic Logic 60 (2):505-511.
  19.  4
    11th Asian Logic Conference.Qi Feng & Yue Yang - 2010 - Bulletin of Symbolic Logic 16 (2):288-298.
  20.  3
    A Nonlow2 R. E. Degree with the Extension of Embeddings Properties of a Low2 Degree.Richard A. Shore & Yue Yang - 2002 - Mathematical Logic Quarterly 48 (1):131-146.
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  21.  4
    Properly [Image] Enumeration Degrees and the High/Low Hierarchy.Matthew Giorgi, Andrea Sorbi & Yue Yang - 2006 - Journal of Symbolic Logic 71 (4):1125 - 1144.
    We show that there exist downwards properly $\Sigma _{2}^{0}$ (in fact noncuppable) e-degrees that are not high. We also show that every high e-degree bounds a noncuppable e-degree.
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