Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Period of the subtraction games   Subtraction games is a class of impartial combinatorial games, They with
finite subtraction sets are known to have periodic nim-sequences. So people try
to find the regular of the games. But for specific of Sprague-Grundy Theory, it
is too difficult to find, they obtained some conclusions just by simple
observing. This paper used PTFN algorithm to analyze the period of the
Subtraction games. It is more suitable than Sprague-Grundy Theory, and this
paper obtained four conclusions by PTFN algorithm . This algorithm provide a
new direction to study the subtraction games' period.

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The categories of this paper are: cond-mat
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The categories of this paper are: eess
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The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
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The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: bayes-an
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The categories of this paper are: math
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The categories of this paper are: physics
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The categories of this paper are: hep-th
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The categories of this paper are: comp-gas
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The categories of this paper are: stat
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The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th
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The categories of this paper are: nlin