Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quaternary Constant-Amplitude Codes for Multicode CDMA   A constant-amplitude code is a code that reduces the peak-to-average power
ratio (PAPR) in multicode code-division multiple access (MC-CDMA) systems to
the favorable value 1. In this paper quaternary constant-amplitude codes (codes
over Z_4) of length 2^m with error-correction capabilities are studied. These
codes exist for every positive integer m, while binary constant-amplitude codes
cannot exist if m is odd. Every word of such a code corresponds to a function
from the binary m-tuples to Z_4 having the bent property, i.e., its Fourier
transform has magnitudes 2^{m/2}. Several constructions of such functions are
presented, which are exploited in connection with algebraic codes over Z_4 (in
particular quaternary Reed-Muller, Kerdock, and Delsarte-Goethals codes) to
construct families of quaternary constant-amplitude codes. Mappings from binary
to quaternary constant-amplitude codes are presented as well.

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The categories of this paper are: physics
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The categories of this paper are: astro-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-bio
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The categories of this paper are: plasm-ph
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The categories of this paper are: math-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: alg-geom
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The categories of this paper are: econ
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The categories of this paper are: chem-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: eess
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The categories of this paper are: hep-lat
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The categories of this paper are: supr-con