Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Further simplification of the constraints of four-dimensional gravity   The super-Hamiltonian of 4-dimensional gravity as simplified by Ashtekar
through the use of gauge potential and densitized triad variables can
furthermore be succinctly expressed as a Poisson bracket between the volume
element and other fundamental gauge-invariant elements of 3-geometry. This
observation naturally suggests a reformulation of non-perturbative quantum
gravity wherein the Wheeler-DeWitt Equation is identical to the requirement of
the vanishing of the corresponding commutator. Moreover, this reformulation
singles out spin network states as the preeminent basis for expansion of all
physical states.

14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con