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每一个非零的可计算可枚举强有界图灵度都具有反成杯性质(英文)

Every Nonzero c.e.Strongly Bounded Turing Degree has the Anti-cupping Property

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【作者】 克劳斯·安博司比斯王玮

【Author】 Klaus Ambos-Spies Department of Mathematics and Computer Science,Ruprecht-Karls-Universitat Wei Wang Institute of Logic and Cognition,Department of Philosophy,Sun Yat-sen University

【机构】 德国海德堡大学数学与计算机科学系中山大学逻辑与认知研究所、哲学系

【摘要】 可计算Lipschitz图灵归约(cl-归约)是指用函数被x→x+c约束的图灵归约,其中c是常数;而ibT归约则通过限制用函数为恒等函数得到。我们通称cl-,ibT-归约为强有界图灵归约。我们证明:对于r=cl,ibT,在可计算可枚举r-度构成的偏序结构(Rr,≤)中,每一个非零的a都具有反成杯性质。为此,我们证明一个新结论:对于每一个不可计算的可计算可枚举集合A,都存在一个不可计算的可计算可枚举B,使得对所有满足A≤wtt C的可计算可枚举集合C都有B≤ibT C。结合关于可计算偏移的已知性质,我们便可得到上述主要定理。

【Abstract】 The strongly bounded Turing reducibilities r = cl(computable Lipschitz reducibility) and r = ibT(identity bounded Turing reducibility) are defined in terms of Turing reductions where the use function is bounded by the identity function up to an additive constant and the identity function,respectively.We show that,for r = ibT,cl,every computably enumerable (c.e.) r-degree a>0 has the anti-cupping property in the partial ordering(Rr,<) of the c.e.r-degrees. The proof is based on(1) the(new) result,that,for any noncomputable c.e.set A there is a noncomputable c.e.set B such that B≤ibT C for all c.e.sets C with A≤wtt C and(2) some (old) observations on computable shifts.

【关键词】 图灵恒等函数主要定理stringTuring归约lattertruthelementaryinfinitely
【基金】 supported by the Sino-German binational grant "Computability and Complexity in Analysis:Towards a Sound Foundation for Scientific Computations"(NSFC 10911130011 and DFG 446 CHV 113/266/0-1);partially supported by NSFC 11001281
  • 【文献出处】 逻辑学研究 ,Studies in Logic , 编辑部邮箱 ,2012年03期
  • 【分类号】TP301.4;O141.3
  • 【下载频次】37
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