Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tetrads in Geometrodynamics   A new tetrad is introduced within the framework of geometrodynamics for
non-null electromagnetic fields. This tetrad diagonalizes the electromagnetic
stress-energy tensor and allows for maximum simplification of the expression of
the electromagnetic field. The Einstein-Maxwell equations will also be
simplified.

8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat