Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Asymptotic behaviours of the heat kernel in covariant perturbation
  theory   The trace of the heat kernel is expanded in a basis of nonlocal curvature
invariants of $N$th order. The coefficients of this expansion (the nonlocal
form factors) are calculated to third order in the curvature inclusive. The
early-time and late-time asymptotic behaviours of the trace of the heat kernel
are presented with this accuracy. The late-time behaviour gives the criterion
of analyticity of the effective action in quantum field theory. The latter
point is exemplified by deriving the effective action in two dimensions.

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The categories of this paper are: hep-ex
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The categories of this paper are: astro-ph
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
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The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
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The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: quant-ph
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The categories of this paper are: physics
15
The categories of this paper are: nucl-ex