Searching for authors named "George Barmpalias" – sorted by Relevance.
14 documents found, showing 1 through 10.
Next 10 →
-
Random non-cupping revisited
- …Abstract. Say that Y has the strong random anticupping property if there is a set A such that for every Martin-Löf random set R Y ≤T A ⊕ R ⇒ Y ≤T R (in this case A is an anticupping witness for Y). Nies has shown that every random ∆ 0 2 set has the strong random anticupping property via a promptly s…
- Cited by 4 (0 self) – Add To MetaCart
-
Approximation Representations for Reals and their wtt-Degrees
- …Abstract. We study the approximation properties of computably enumerable reals. We deal with a natural notion of approximation representation and study their wtt-degrees. Also, we show that a single representation may correspond to a quite diverse variety of reals. 1.…
- Cited by 2 (2 self) – Add To MetaCart
-
Hypersimplicity and Semicomputability in the Weak Truth Table Degrees
- …Abstract. We study the classes of hypersimple and semicomputable sets as well as their intersection in the weak truth table degrees. We construct degrees that are not bounded by hypersimple degrees outside any non-trivial upper cone of Turing degrees and show that the hypersimple-free c.e. wtt degre…
- Cited by 4 (2 self) – Add To MetaCart
-
Approximation representations for ∆2 reals
- …Abstract. We study ∆2 reals x in terms of how they can be approximated symmetrically by a computable sequence of rationals. We deal with a natural notion of ‘approximation representation ’ and study how these are related computationally for a fixed x. This is a continuation of earlier work; it aims …
- Cited by 2 (2 self) – Add To MetaCart
-
Computably enumerable sets in the Solovay and the strong weak truth table degrees
- …Abstract. The strong weak truth table reducibility was suggested by Downey, Hirschfeldt, and LaForte as a measure of relative randomness, alternative to the Solovay reducibility. It also occurs naturally in proofs in classical computability theory as well as in the recent work of Soare, Nabutovsky a…
- Cited by 2 (2 self) – Add To MetaCart
-
A cappable almost everywhere dominating computably enumerable degree
- …Abstract. We show that there exists an almost everywhere (a.e.) dominating computably enumerable (c.e.) degree which is half of a minimal pair. 1.…
- Cited by 4 (4 self) – Add To MetaCart
-
K-TRIVIAL DEGREES AND THE JUMP-TRACEABILITY HIERARCHY
- …Abstract. For every order h such that P n 1/h(n) is finite, every K-trivial degree is h-jump-traceable. This motivated Cholak, Downey and Greenberg [2] to ask whether this traceability property is actually equivalent to K-triviality, thereby giving the hoped for combinatorial characterisation of low…
- Add To MetaCart
-
Monotonically computable real numbers
- …Key words h-monotone computable real, ω-monotone computable real.…
- Cited by 7 (5 self) – Add To MetaCart
-
Immunity Properties and the n-C.E. Hierarchy
- …Abstract. We extend Post’s programme to finite levels of the Ershov hierarchy of ∆2 sets, and characterise, in the spirit of Post [9], the degrees of the immune and hyperimmune d.c.e. sets. We also show that no properly d.c.e. set can be hh-immune, and indicate how to generalise these results to n-c…
- Cited by 2 (1 self) – Add To MetaCart
-
Randomness, lowness and degrees
- …Abstract. We say that A ≤LR B if every B-random number is Arandom. Intuitively this means that if oracle A can identify some patterns on some real γ, oracle B can also find patterns on γ. In other words, B is at least as good as A for this purpose. We study the structure of the LR degrees globally a…
- Cited by 3 (1 self) – Add To MetaCart
Showing 1 through 10.
Next 10 →
