Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Extra pearls in graph theory   This is a supplement for "Pearls in graph theory" -- a textbook written by
Nora Hartsfield and Gerhard Ringel.
  Probabilistic method, Deletion-contraction formulas, Matrix theorem,
Graph-polynomials, Generating functions, Minimum spanning trees, Marriage
theorem and its relatives, Toroidal graphs, Rado graph.

3
The categories of this paper are: physics
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph