Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Estimating and increasing the structural robustness of a network   The capability of a network to cope with threats and survive attacks is
referred to as its robustness. This paper discusses one kind of robustness,
commonly denoted structural robustness, which increases when the spectral
radius of the adjacency matrix associated with the network decreases. We
discuss computational techniques for identifying edges, whose removal may
significantly reduce the spectral radius. Nonsymmetric adjacency matrices are
studied with the aid of their pseudospectra. In particular, we consider
nonsymmetric adjacency matrices that arise when people seek to avoid being
infected by Covid-19 by wearing facial masks of different qualities.

13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom