Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A pre-order principle and set-valued Ekeland variational principle   We establish a pre-order principle. From the principle, we obtain a very
general set-valued Ekeland variational principle, where the objective function
is a set-valued map taking values in a quasi ordered linear space and the
perturbation contains a family of set-valued maps satisfying certain property.
From this general set-valued Ekeland variational principle, we deduce a number
of particular versions of set-valued Ekeland variational principle, which
include many known Ekeland variational principles, their improvements and some
new results.

16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin