Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A New Upper Bound on the Average Error Exponent for Multiple-Access
  Channels   A new lower bound for the average probability or error for a two-user
discrete memoryless (DM) multiple-access channel (MAC) is derived. This bound
has a structure very similar to the well-known sphere packing packing bound
derived by Haroutunian. However, since explicitly imposes independence of the
users' input distributions (conditioned on the time-sharing auxiliary variable)
results in a tighter sphere-packing exponent in comparison to Haroutunian's.
Also, the relationship between average and maximal error probabilities is
studied. Finally, by using a known sphere packing bound on the maximal
probability of error, a lower bound on the average error probability is
derived.

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The categories of this paper are: cond-mat
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The categories of this paper are: stat
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The categories of this paper are: q-fin
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The categories of this paper are: math-ph
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The categories of this paper are: hep-th
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The categories of this paper are: adap-org
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The categories of this paper are: q-alg
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The categories of this paper are: physics
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: funct-an
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-ex
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The categories of this paper are: gr-qc
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The categories of this paper are: econ