Title
Connectivity in Random Annulus Graphs and the Geometric Block Model.
Abstract
Random geometric graphs are the simplest, and perhaps the earliest possible random graph model of spatial networks, introduced by Gilbert in 1961. In the most basic setting, a random geometric graph $G(n,r)$ has $n$ vertices. Each vertex of the graph is assigned a real number in $[0,1]$ randomly and uniformly. There is an edge between two vertices if the corresponding two random numbers differ by at most $r$ (to mitigate the boundary effect, let us consider the Lee distance here, $d_L(u,v) = min{|u-v|, 1-|u-v|}$). It is well-known that the connectivity threshold regime for random geometric graphs is at $r approx frac{log n}{n}$. In particular, if $r = frac{alog n}{n}$, then a random geometric graph is connected with high probability if and only if $a u003e 1$. Consider $G(n,frac{(1+epsilon)log{n}}{n})$ for any $epsilon u003e0$ to satisfy the connectivity requirement and delete half of its edges which have distance at most $frac{log{n}}{2n}$. It is natural to believe that the resultant graph will be disconnected. Surprisingly, we show that the graph still remains connected! Formally, generalizing random geometric graphs, we define a random annulus graph $G(n, [r_1, r_2]), r_1 frac12$ and $a u003e1$. That is $G(n, [0,frac{0.99log n}{n}])$ is not connected but $G(n,[frac{0.50 log n}{n},frac{1+epsilon log n}{n}])$ is. This result is then used to give improved lower and upper bounds on the recovery threshold of the geometric block model.
Year
Venue
Field
2018
APPROX-RANDOM
Discrete mathematics,Binary logarithm,Lee distance,Combinatorics,Random graph,Approx,Vertex (geometry),Generalization,Random geometric graph,Real number,Mathematics
DocType
Volume
Citations 
Journal
abs/1804.05013
1
PageRank 
References 
Authors
0.35
0
4
Name
Order
Citations
PageRank
Sainyam Galhotra110710.96
Arya Mazumdar230741.81
Soumyabrata Pal323.76
Barna Saha462637.56