Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Flag-transitive block designs and finite exceptional simple groups of
  Lie type   In this article, we study $2$-designs with $\gcd(r,\lambda)=1$ admitting a
flag-transitive almost simple automorphism group with socle a finite simple
exceptional group of Lie type. We obtain four infinite families of such designs
and provide some examples in each of these families.

6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs