Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Remark on Letzter-Makar-Limanov Invariants   We give a natural cohomological interpretation of Letzter-Makar-Limanov
invariants for rings of differential operators on algebraic curves.

12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
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
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph