Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exact and fast inversion of the approximate discrete Radon transform
  from partial data   We give an exact inversion formula for the approximate discrete Radon
transform introduced in [Brady, SIAM J. Comput., 27(1), 107--119] that is of
cost $O(N \log N)$ for a square 2D image with $N$ pixels and requires only
partial data.

6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio