Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Canonical Laplacian on the Algebra of Densities on a Projectively
  Connected Manifold   On a manifold with a projective connection we canonically assign a second
order differential operator acting on the algebra of all densities to any
tensor density $S^{ij}$ of fixed weight $\lambda$. In particular, this implies
that on any projectively connected manifold, a `bracket' (symmetric
biderivation) on the algebra of functions extends canonically to the algebra of
densities.

21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg