Coherence of reducibilities with randomness notions

News
1 Feb 2016, accepted by TOCS

Title
Coherence of reducibilities with randomness notions

Type
Full paper

Journal
Theory of Computing Systems – October 2018, Volume 62, Issue 7, pp 1599–1619
DOI: https://doi.org/10.1007/s00224-017-9752-2

Abstract
Loosely speaking, when A is “more random” than B and B is “random”,
then A should be random.
The theory of algorithmic randomness has some formulations of “random” sets
and “more random” sets.
In this paper, we study which pairs (R,r) of randomness notions R
and reducibilities r have the follwing property:
if A is r-reducible to B and A is R-random,
then B should be R-random.
The answer depends on the notions R and r.
The implications hold for most pairs, but not for some.
We also give characterizations of n-randomness via complexity.

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