Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Thermodynamically stable equal-module exchange magnetic classes   It is shown that within the framework of application of the general scheme of
the Landau theory of phase transitions to the magnetic crystals the equilibrium
and stable equal-module exchange structures automatically appears in addition
to the other magnetic states. No additional conditions such as the existence of
the Andreev-Marchenko spin scalar are needed. Furthermore, they are not
constrained by the dimensionality of irreducible representation as it typically
takes place for the Andreev-Marchenko-type structures.

3
The categories of this paper are: physics
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
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The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
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The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th