Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Courant algebroid and Lie bialgebroid contractions   Contractions of Leibniz algebras and Courant algebroids by means of
(1,1)-tensors are introduced and studied. An appropriate version of Nijenhuis
tensors leads to natural deformations of Dirac structures and Lie bialgebroids.
One recovers presymplectic-Nijenhuis structures, Poisson-Nijenhuis structures,
and triangular Lie bialgebroids as particular examples.

8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
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The categories of this paper are: nucl-th
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The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
24
The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys