Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Model reduction by separation of variables: a comparison between
  Hierarchical Model reduction and Proper Generalized Decomposition   Hierarchical Model reduction and Proper Generalized Decomposition both
exploit separation of variables to perform a model reduction. After setting the
basics, we exemplify these techniques on some standard elliptic problems to
highlight pros and cons of the two procedures, both from a methodological and a
numerical viewpoint.

5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat