Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Microlocal Methods for The Elastic Travel Time Tomography Problem for
  Transversely Isotropic Media   We study the travel time tomography problem for transversely isotropic media
using the artificial boundary method used in works in X-ray tomography and
boundary rigidity problems. The analysis involved requires a modification of
the scattering pseudodifferential calculus in order to provide parametrices for
operators which are degenerately elliptic; such a calculus is constructed in
this paper and used to solve the tomography problem of interest.

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The categories of this paper are: quant-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg
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The categories of this paper are: stat
7
The categories of this paper are: hep-th
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The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
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The categories of this paper are: cmp-lg
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The categories of this paper are: nucl-ex
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The categories of this paper are: gr-qc
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The categories of this paper are: comp-gas
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The categories of this paper are: eess
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The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol