Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On Homeomorphically Irreducible Spanning Trees in Cubic Graphs   A spanning tree without a vertex of degree two is called a Hist which is an
abbreviation for homeomorphically irreducible spanning tree. We provide a
necessary condition for the existence of a Hist in a cubic graph. As one
consequence, we answer affirmatively an open question on Hists by Albertson,
Berman, Hutchinson and Thomassen.

12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
24
The categories of this paper are: dg-ga
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an