Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Inconsistencies of a purported probability current in the
  Duffin-Kemmer-Petiau theory   The Duffin-Kemmer-Petiau (DKP) equation with a square step potential is used
in a simple way with polymorphic purposes. It proves adequate to refuse a
proposed new current that is currently interpreted as a probability current,to
show that the Klein paradox does exist in the DKP theory and to revise other
minor misconceptions diffused in the literature.

34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
0
The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ