Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Pullbacks of Principal Coactions   We prove that the class of principal coactions is closed under one-surjective
pullbacks in an appropriate category of algebras equipped with left and right
coactions. This allows us to handle cases of C*-algebras lacking two different
non-trivial ideals. It also allows us to go beyond the category of comodule
algebras. As an example of the former, we carry out an index computation for
noncommutative line bundles over the standard Podles sphere using the
Mayer-Vietoris type arguments afforded by a one-surjective pullback
presentation of the C*-algebra of this quantum sphere. To instantiate the
latter, we define a family of coalgebraic noncommutative deformations of the
U(1)-principal bundle S^7 --> CP^3.

22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol