Frank Stephan

9 citations · 9 across the 3 of their papers we have counts for

collaborators

3 papers

math.LO2019

On the order dimension of locally countable partial orderings

Kojiro Higuchi, Steffen Lempp, Diip Raghavan +1

We show that the order dimension of the partial order of all finite subsets of $κ$ under set inclusion is $lo g_{2} (lo g_{2} (κ))$ whenever $κ$ is an infinite cardinal. We also…

math.LO2014★ 9 cited

Higher Kurtz randomness

Bjørn Kjos-Hanssen, André Nies, Frank Stephan +1

A real $x$ is $Δ_{1}^{1}$ -Kurtz random ( $Π_{1}^{1}$ -Kurtz random) if it is in no closed null $Δ_{1}^{1}$ set ( $Π_{1}^{1}$ set). We show that there is a cone of $Π_{1}^{1}$ -Kurtz random hyperdegrees. W…

math.LO2014

On Martin's Pointed Tree Theorem

Rupert Hölzl, Frank Stephan, Liang Yu

We investigate the reverse mathematics strength of Martin's pointed tree theorem (MPT) and one of its variants, weak Martin's pointed tree theorem (wMPT).