Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hochschild and ordinary cohomology rings of small categories   Let C be a small category and k a field. There are two interesting
mathematical subjects: the category algebra kC and the classifying space
|C|=BC. We study the ring homomorphism HH*(kC) --> H*(|C|,k) and prove it is
split surjective. This generalizes the well-known results for groups and
posets. Based on this result, we construct a seven-dimensional category algebra
whose Hochschild cohomology ring modulo nilpotents is not finitely generated,
against a conjecture of Snashall and Solberg.

17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
18
The categories of this paper are: econ
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th