Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Black Holes Constitute All Dark Matter   The dimensionless entropy, ${\cal S} \equiv S/k$, of the visible universe,
taken as a sphere of radius 50 billion light years with the Earth at its
"center", is discussed. An upper limit ($10^{112}$), and a lower limit
($10^{102}$), for ${\cal S}$ are introduced. It is suggested that
intermediate-mass black holes (IMBHs) constitute all dark matter, and that they
dominate ${\cal S}$.

35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
16
The categories of this paper are: stat
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
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The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom