Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Relativistic Quaternionic Wave Equation II   Further results are reported for the one-component quaternionic wave equation
recently introduced. A Lagrangian is found for the momentum-space version of
the free equation; and another, nonlocal in time, is found for the complete
equation. Further study of multi-particle systems has us looking into the
mathematics of tensor products of Hilbert spaces. The principles of linearity
and superposition are also clarified to good effect in advancing the
quaternionic theory.

27
The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
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The categories of this paper are: dg-ga
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The categories of this paper are: q-alg
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The categories of this paper are: funct-an
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The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio