Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On signed graphs whose spectral radius does not exceed
  $\sqrt{2+\sqrt{5}}$   The Hoffman program with respect to any real or complex square matrix $M$
associated to a graph $G$ stems from Hoffman's pioneering work on the limit
points for the spectral radius of adjacency matrices of graphs does not exceed
$\sqrt{2+\sqrt{5}}$. A signed graph $\dot{G}=(G,\sigma)$ is a pair
$(G,\sigma),$ where $G=(V,E)$ is a simple graph and $\sigma: E(G)\rightarrow
\{+1,-1\}$ is the sign function. In this paper, we study the Hoffman program of
signed graphs. Here, all signed graphs whose spectral radius does not exceed
$\sqrt{2+\sqrt{5}}$ will be identified.

22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
23
The categories of this paper are: solv-int
26
The categories of this paper are: bayes-an
24
The categories of this paper are: dg-ga