Abstract
The notion of superhigh computably enumerable (c.e.) degrees was first introduced by (Mohrherr in Z Math Logik Grundlag Math 32: 5–12, 1986) where she proved the existence of incomplete superhigh c.e. degrees, and high, but not superhigh, c.e. degrees. Recent research shows that the notion of superhighness is closely related to algorithmic randomness and effective measure theory. Jockusch and Mohrherr proved in (Proc Amer Math Soc 94:123–128, 1985) that the diamond lattice can be embedded into the c.e. tt-degrees preserving 0 and 1 and that the two atoms can be low. In this paper, we prove that the two atoms in such embeddings can also be superhigh.
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Cenzer is partially supported by NSF grants DMS-0554841 and DMS-652372.
Wu is partially supported by AcRF grants RG58/06 and RG37/09 from Singapore MoE.
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Cenzer, D., Franklin, J.N.Y., Liu, J. et al. A superhigh diamond in the c.e. tt-degrees. Arch. Math. Logic 50, 33–44 (2011). https://doi.org/10.1007/s00153-010-0198-3
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DOI: https://doi.org/10.1007/s00153-010-0198-3