An 
percolation is a discrete
percolation model in which the underlying point
lattice graph 
has the properties that each of its graph
vertices is occupied by an atom either of type 
or of type 
, that there is a probability 
that any given vertex is occupied by
an atom of type 
,
and that different vertices are occupied independently
of each other.
In this model, a graph edge of 
is said to be open if its end vertices are occupied by atoms
of different types and is said to be closed otherwise. The idea is based on the hypothesis
that dissimilar atoms bond together whereas similar atoms repel one another.
This model is sometimes studied under the title antipercolation.
