Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Almost complex structures in 6D with nondegenerate Nijenhuis tensors and
  large symmetry groups   For an almost complex structure $J$ in dimension 6 with nondegenerate
Nijenhuis tensor $N_J$, the automorphism group $G=Aut(J)$ of maximal dimension
is the exceptional Lie group $G_2$. In this paper we establish that the
sub-maximal dimension of automorphism groups of almost complex structures with
nondegenerate $N_J$, i.e. the largest realizable dimension that is less than
14, is $\dim G=10$. Next we prove that only 3 spaces realize this, and all of
them are strictly nearly (pseudo-) K\"ahler and globally homogeneous. Moreover,
we show that all examples with $\dim Aut(J)=9$ have semi-simple isotropy.

34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph