Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The instanton contributions to Yang-Mills theory on the torus:
  localization, Wilson loops and the perturbative expansion   The instanton contributions to the partition function and to homologically
trivial Wilson loops for a U(N) Yang-Mills theory on a torus $T^2$ are
analyzed. An exact expression for the partition function is obtained as a sum
of contributions localized around the classical solutions of Yang-Mills
equations, that appear according to the general classification of Atiyah and
Bott. Explicit expressions for the exact Wilson loop averages are obtained when
N=2, N=3. For general $N$ the contribution of the zero-instanton sector has
been carefully derived in the decompactification limit, reproducing the sum of
the perturbative series on the plane, in which the light-cone gauge Yang-Mills
propagator is prescribed according to Wu-Mandelstam-Leibbrandt (WML). Agreement
with the results coming from $S^2$ is therefore obtained, confirming the truly
perturbative nature of the WML computations.

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The categories of this paper are: patt-sol
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The categories of this paper are: adap-org
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The categories of this paper are: solv-int
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The categories of this paper are: funct-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: comp-gas
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The categories of this paper are: chem-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: ao-sci
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The categories of this paper are: math-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: acc-phys
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The categories of this paper are: supr-con
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The categories of this paper are: physics
2
The categories of this paper are: math
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The categories of this paper are: q-fin