Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quasi, twisted, and all that... in Poisson geometry and Lie algebroid
  theory   Motivated by questions from quantum group and field theories, we review
structures on manifolds that are weaker versions of Poisson structures, and
variants of the notion of Lie algebroid. We give a simple definition of the
Courant algebroids and introduce the notion of a deriving operator for the
Courant bracket of the double of a proto-bialgebroid. We then describe and
relate the various quasi-Poisson structures, which have appeared in the
literature since 1991, and the twisted Poisson structures studied by Severa and
Weinstein.

33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th