D. Hirschfeldt

activity

20112022

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

43 citations · 55 across the 12 of their papers we have counts for

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Showing 2021Show all

2 papers · 1 filter

math.LO2021

A Feiner Look at the Intermediate Degrees

Denis R. Hirschfeldt, Asher M. Kach, Antonio Montalbán

We say that a set $S$ is $Δ_{(n)}^{0} (X)$ if membership of $n$ in $S$ is a $Δ_{n}^{0} (X)$ question, uniformly in $n$ . A set $X$ is low for $Δ$ -Feiner if every set $S$ that is $Δ^0_{(n)…

math.LO2021★ 1 cited

Coarse computability, the density metric, Hausdorff distances between Turing degrees, perfect trees, and reverse mathematics

Denis R. Hirschfeldt, Carl G. Jockusch, Paul E. Schupp

The coarse similarity class $[A]$ of $A$ is the set of all $B$ whose symmetric difference with $A$ has asymptotic density 0. There is a natural metric $δ$ on the space $\mathcal{S}…