Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the number of outer connected dominating sets of graphs   Let $G=(V,E)$ be a simple graph. A set $S\subseteq V(G)$ is called an
outer-connected dominating set (or ocd-set) of $G$, if $S$ is a dominating set
of $G$ and either $S=V(G)$ or $V\backslash S$ is a connected graph. In this
paper we introduce a polynomial which its coefficients are the number of
ocd-sets of $G$. We obtain some properties of this polynomial and its
coefficients. Also we compute this polynomial for some specific graphs.

29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol