Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the existence of a variational principle for deterministic cellular
  automaton models of highway traffic flow   It is shown that a variety of deterministic cellular automaton models of
highway traffic flow obey a variational principle which states that, for a
given car density, the average car flow is a non-decreasing function of time.
This result is established for systems whose configurations exhibits local jams
of a given structure. If local jams have a different structure, it is shown
that either the variational principle may still apply to systems evolving
according to some particular rules, or it could apply under a weaker form to
systems whose asymptotic average car flow is a well-defined function of car
density. To establish these results it has been necessary to characterize among
all number-conserving cellular automaton rules which ones may reasonably be
considered as acceptable traffic rules. Various notions such as free-moving
phase, perfect and defective tiles, and local jam play an important role in the
discussion. Many illustrative examples are given.

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The categories of this paper are: gr-qc
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ex
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The categories of this paper are: funct-an
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The categories of this paper are: dg-ga
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The categories of this paper are: eess
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The categories of this paper are: stat
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The categories of this paper are: mtrl-th
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The categories of this paper are: econ
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The categories of this paper are: adap-org
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The categories of this paper are: patt-sol
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The categories of this paper are: astro-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: q-fin
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The categories of this paper are: nlin
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The categories of this paper are: q-bio