Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Graphs with prescribed radius, diameter, and center   Among other things, it is shown that for every pair of positive integers $r$,
$d$, satisfying $1<r<d\leq 2r$, and every finite simple graph $H,$ there is a
connected graph $G$ with diameter $d$, radius $r$, and center $H.$

20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph