Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The complexity of normal form rewrite sequences for Associativity   The complexity of a particular term-rewrite system is considered: the rule of
associativity (x*y)*z --> x*(y*z). Algorithms and exact calculations are given
for the longest and shortest sequences of applications of --> that result in
normal form (NF). The shortest NF sequence for a term x is always n-drm(x),
where n is the number of occurrences of * in x and drm(x) is the depth of the
rightmost leaf of x. The longest NF sequence for any term is of length
n(n-1)/2.

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The categories of this paper are: hep-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-ex
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The categories of this paper are: supr-con
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The categories of this paper are: solv-int
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The categories of this paper are: q-fin
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The categories of this paper are: adap-org
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The categories of this paper are: nlin
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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: math
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The categories of this paper are: stat
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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: atom-ph