The Gamma question for many-one degrees
Abstract
A set is coarsely computable with density if there is an algorithm for deciding membership in which always gives a (possibly incorrect) answer, and which gives a correct answer with density at least . To any Turing degree we can assign a value : the minimum, over all sets in , of the highest density at which is coarsely computable. The closer is to , the closer is to being computable. Andrews, Cai, Diamondstone, Jockush, and Lempp noted that can take on the values , , and , but not any values in strictly between and . They asked whether the value of can be strictly between and . This is the Gamma question. Replacing Turing degrees by many-one degrees, we get an analogous question, and the same arguments show that can take on the values , , and , but not any values strictly between and . We will show that for any , there is an -degree with . Thus the range of is . Benoit Monin has recently announced a solution to the Gamma question for Turing degrees. Interestingly, his solution gives the opposite answer: the only possible values of are , , and .
Keywords
Cite
@article{arxiv.1606.05701,
title = {The Gamma question for many-one degrees},
author = {Matthew Harrison-Trainor},
journal= {arXiv preprint arXiv:1606.05701},
year = {2017}
}
Comments
9 pages