Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spacetime algebra and electron physics   This paper surveys the application of geometric algebra to the physics of
electrons. It first appeared in 1996 and is reproduced here with only minor
modifications. Subjects covered include non-relativistic and relativistic
spinors, the Dirac equation, operators and monogenics, the Hydrogen atom,
propagators and scattering theory, spin precession, tunnelling times, spin
measurement, multiparticle quantum mechanics, relativistic multiparticle wave
equations, and semiclassical mechanics.

30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
21
The categories of this paper are: adap-org
23
The categories of this paper are: solv-int