The disk model is the standard Boolean-Poisson model in two-dimensional continuum
percolation theory. In particular, the disk model is characterized by the existence
of a Poisson process 
in 
which distributes the centers 
of a collection of closed
disks (i.e., two-dimensional closed balls) 
along with a random
process 
which independently assigns random radii 
to each 
.
The disks which make up the disk model are known as random disks.
