Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Inverse square law for the starter intensity of the discrete ordinates
  method in spherical geometry   The angular derivative of the standard form of the transfer equation is shown
to have a non-zero value for the radiation normal incidence. This is
demonstrated by a rigorous proof. The transfer equation for the starter
intensity turned out to be Euler first order equation its solution obeys the
inverse square law.

24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex