Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: VADU 2018 Open Problem Session   We state the problems discussed in the open problem session at Variational
Analysis Down Under (VADU2018) conference held in honour of Prof. Asen
Dontchev's 70th birthday on 19--21 February 2018 at Federation University
Australia, https://sites.rmit.edu.au/asen/.

22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics