Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An electromagnetic trinity from "negative permittivity" and "negative
  permeability"   An electromagnetic trinity comprising vacuum, anti--vacuum, and nihility is
postulated -- after making use of materials with "negative permittivity" and
"negative permeability" -- to illuminate the structure of electromagnetic
theory, at least insofar as the relationship of phase velocity with Poynting
vector is concerned.

31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th