Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quasi-Concavity for Gaussian Multicast Relay Channels   Standard upper and lower bounds on the capacity of relay channels are cut-set
(CS), decode-forward (DF), and quantize-forward (QF) rates. For real additive
white Gaussian noise (AWGN) multicast relay channels with one source node and
one relay node, these bounds are shown to be quasi-concave in the receiver
signal-to-noise ratios and the squared source-relay correlation coefficient.
Furthermore, the CS rates are shown to be quasi-concave in the relay position
for a fixed correlation coefficient, and the DF rates are shown to be
quasi-concave in the relay position. The latter property characterizes the
optimal relay position when using DF.

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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
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
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The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
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The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
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The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an