Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A Dense Packing of Regular Tetrahedra   We construct a dense packing of regular tetrahedra, with packing density $D >
>.7786157$.

13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: solv-int
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The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
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The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
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The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
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The categories of this paper are: stat
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The categories of this paper are: adap-org
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The categories of this paper are: eess