Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Connes-Moscovici Hopf algebra associated to the diffeomorphisms
  of a manifold   For our own education, we reconstruct the Hopf algebra of Connes and
Moscovici obtained by the action of vector fields on a crossed product of
functions by diffeomorphisms. We extend the realization of that Hopf algebra in
terms of rooted trees as given by Connes and Kreimer from dimension one to
arbitrary dimension of the manifold. In principle there is no modification, but
in higher dimension one has to be careful with the order of cuts. The order
problem leads us to speculate that in quantum field theory the sum of Feynman
graphs which corresponds to an element of the Connes-Moscovici Hopf algebra
could have a larger symmetry than the individual graphs.

6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph