Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Maximizing bandgaps in two-dimensional photonic crystals: a variational
  algorithm   We present an algorithm for the maximization of photonic bandgaps in
two-dimensional crystals. Once the translational symmetries of the underlying
structure have been imposed, our algorithm finds a global maximal (and
complete, if one exists) bandgap. Additionally, we prove two remarkable results
related to maximal bandgaps: the so-called `maximum contrast' rule, and about
the location in the Brillouin zone of band edges.

15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs