Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Schwinger's principle in Einstein-Cartan gravity   By applying Schwinger's variational principle to the Einstein-Cartan action
for the gravitational field, we derive quantum commutation relations between
the metric and torsion tensors.

29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
3
The categories of this paper are: physics