C. Jockusch

activity

19972021

most citedThe Strength of Some Combinatorial Principles Related to Ramsey's Theorem for Pairs

43 citations · 87 across the 9 of their papers we have counts for

collaborators

Showing 2013 · math.LOShow all

2 papers · 2 filters

math.LO2013★ 1 cited

Asymptotic density and the Ershov hierarchy

Rod Downey, Carl Jockusch, Timothy H. McNicholl +1

We classify the asymptotic densities of the $Δ_{2}^{0}$ sets according to their level in the Ershov hierarchy. In particular, it is shown that for $n \geq 2$ , a real $r \in [0, 1]$ is t…

math.LO2013

Asymptotic Density and Computably Enumerable Sets

Rodney G. Downey, Carl G. Jockusch, Paul E. Schupp

We study connections between classical asymptotic density and c.e. sets. We prove that a c.e. Turing degree d is not low if and only if d contains a c.e. set A of density 1 which h…