Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Choi-Lam analogue of Hilbert's 1888 theorem for Symmetric Forms   A famous theorem of Hilbert from 1888 states that a positive semidefinite
(psd) real form is a sum of squares (sos) of real forms if and only if $n=2$ or
$d=1$ or $(n,2d)=(3,4)$, where $n$ is the number of variables and $2d$ the
degree of the form. In 1976, Choi and Lam proved the analogue of Hilbert's
Theorem for symmetric forms by assuming the existence of psd not sos symmetric
$n$-ary quartics for $n \geq 5$. In this paper we complete their proof by
constructing explicit psd not sos symmetric $n$-ary quartics for $n \geq 5$.

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The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: eess
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: supr-con
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom