Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Adjoints and Formal Adjoints of Matrices of Unbounded Operators   In this paper we {\em discuss} diverse aspects of mutual relationship between
adjoints and formal adjoints of unbounded operators bearing a matrix structure.
We emphasize on the behaviour of row and column operators as they turn out to
be the germs of an arbitrary matrix operator, providing most of the information
about the latter {as it is the troublemaker}.

18
The categories of this paper are: econ
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci