Daniel Turetsky

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We examine the sequences A that are low for dimension, i.e., those for which the effective (Hausdorff) dimension relative to A is the same as the unrelativized effective dimension. Lowness for dimension is a weakening of lowness for randomness, a central notion in effective randomness. By considering analogues of characterizations of lowness for randomness,(More)
The spinal cords of 28 scoliosis patients between the ages of 1 month and 17 years were examined with magnetic resonance (MR) imaging. Complete visualization was obtained in all cases. In 15 patients (53%) neuropathologic abnormalities demonstrated by MR imaging significantly affected their clinical course, including tethered cords (n = 7), syringomyelia (n(More)
A technique for performing core biopsies of indeterminate masses of the extracranial head and neck is described. Four patients with suspicious masses of the extracranial head and neck underwent coaxial core biopsies through an 18-gauge Hawkins-Akins blunt tip needle. Three of the four patients had diagnostically adequate samples. There were no neurologic or(More)
The current work introduces the notion of pdominant sets and studies their recursion-theoretic properties. Here a set A is called pdominant iff there is a partial A-recursive function ψ such that for every partial recursive function φ and almost every x in the domain of φ there is a y in the domain of ψ with y ≤ x and ψ(y) > φ(x). While there is a full Π 1(More)
We show the existence of noncomputable oracles which are low for Demuth randomness, answering a question in [14] (also Problem 5.5.19 in [33]). We fully characterize lowness for Demuth randomness using an appropriate notion of traceability. Central to this characterization is a partial relativization of Demuth randomness, which may be more natural than the(More)