Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Feiner Look at the Intermediate Degrees   We say that a set $S$ is $\Delta^0_{(n)}(X)$ if membership of $n$ in $S$ is a
$\Delta^0_{n}(X)$ question, uniformly in $n$. A set $X$ is low for
$\Delta$-Feiner if every set $S$ that is $\Delta^0_{(n)}(X)$ is also
$\Delta^0_{(n)}(\emptyset)$. It is easy to see that every low$_n$ set is low
for $\Delta$-Feiner, but we show that the converse is not true by constructing
an intermediate c.e. set that is low for $\Delta$-Feiner. We also study
variations on this notion, such as the sets that are $\Delta^0_{(bn+a)}(X)$,
$\Sigma^0_{(bn+a)}(X)$, or $\Pi^0_{(bn+a)}(X)$, and the sets that are low,
intermediate, and high for these classes. In doing so, we obtain a result on
the computability of Boolean algebras, namely that there is a Boolean algebra
of intermediate c.e. degree with no computable copy.

27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: plasm-ph
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The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
3
The categories of this paper are: physics
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The categories of this paper are: hep-lat
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The categories of this paper are: econ
5
The categories of this paper are: gr-qc
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The categories of this paper are: nlin
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The categories of this paper are: chao-dyn