Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Model approximations for relative homological algebra   Recently, Chach\'olski, Neeman, Pitsch, and Scherer studied, in a series of
three papers, model approximations for the unbounded category of cochain
complexes over a commutative ring. These approximations allow to construct
relative injective resolutions with respect to particular choices of
injectives. In this paper we define similar model approximations for cochain
complexes on general Grothendieck categories generalizing the previous
constructions and reaching a better understanding of the whole picture.

3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
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The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat
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The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org