Effective Packing Dimension and Traceability
Downey, Rod ; Ng, Keng Meng
Notre Dame J. Formal Logic, Tome 51 (2010) no. 1, p. 279-290 / Harvested from Project Euclid
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We study the Turing degrees which contain a real of effective packing dimension one. Downey and Greenberg showed that a c.e. degree has effective packing dimension one if and only if it is not c.e. traceable. In this paper, we show that this characterization fails in general. We construct a real $A\leq_T\emptyset''$ which is hyperimmune-free and not c.e. traceable such that every real $\alpha\leq_T A$ has effective packing dimension 0. We construct a real $B\leq_T\emptyset'$ which is not c.e. traceable such that every real $\alpha\leq_T B$ has effective packing dimension 0.
Publié le : 2010-04-15
Classification:  effective dimension,  Turing degrees,  03D32 
@article{1276284787,
     author = {Downey, Rod and Ng, Keng Meng},
     title = {Effective Packing Dimension and Traceability},
     journal = {Notre Dame J. Formal Logic},
     volume = {51},
     number = {1},
     year = {2010},
     pages = { 279-290},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1276284787}
}

Downey, Rod; Ng, Keng Meng. Effective Packing Dimension and Traceability. Notre Dame J. Formal Logic, Tome 51 (2010) no. 1, pp.  279-290. http://gdmltest.u-ga.fr/item/1276284787/