Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: \v{C}ech complexes for covers of small categories   We present a combinatorial analogue of the nerve theorem for covers of small
categories, using the Grothendieck construction. We apply our result to prove
the inclusion-exclusion principle for the Euler characteristic of a finite
category.

16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat