Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Positive effective Q12 electrostrictive coefficient in perovskites   It is demonstrated that for classical perovskites such as BaTiO3, SrTiO3 and
PbTiO3 electrostrictive strain induced by an electric field may not obey
traditionally considered "extension along the field, contraction perpendicular
to it" behavior if a sample is cut obliquely to the cubic crystallographic
directions.

14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ