Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hopf algebroids with balancing subalgebra   Recently, S. Meljanac proposed a construction of a class of examples of an
algebraic structure with properties very close to the Hopf algebroids $H$ over
a noncommutative base $A$ of other authors. His examples come along with a
subalgebra $\mathcal{B}$ of $H\otimes H$, here called the balancing subalgebra,
which contains the image of the coproduct and such that the intersection of
$\mathcal{B}$ with the kernel of the projection $H\otimes H\to H\otimes_A H$ is
a two-sided ideal in $\mathcal{B}$ which is moreover well behaved with respect
to the antipode. We propose a set of abstract axioms covering this construction
and make a detailed comparison to the Hopf algebroids of Lu. We prove that
every scalar extension Hopf algebroid can be cast into this new set of axioms.
We present an observation by G. B\"ohm that the Hopf algebroids constructed
from weak Hopf algebras fit into our framework as well. At the end we discuss
the change of balancing subalgebra under Drinfeld-Xu procedure of twisting of
associative bialgebroids by invertible 2-cocycles.

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The categories of this paper are: adap-org
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The categories of this paper are: physics
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The categories of this paper are: comp-gas
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The categories of this paper are: astro-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: econ
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: cmp-lg
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The categories of this paper are: ao-sci
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The categories of this paper are: eess
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The categories of this paper are: supr-con
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The categories of this paper are: q-bio
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The categories of this paper are: q-fin
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The categories of this paper are: quant-ph