Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Primarily orientable graphs   A graph $G$ is primarily orientable if it is possible to orient its edges in
such a way that the resulting oriented graph is prime, i.e., indecomposable
under modular decomposition. We characterize primarily orientable graphs.

25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an