Let 
denote a configuration
with 
points 
and 
lines ("blocks") 
. Then the Levi graph 
, also called the incidence graph, of a configuration
is a bipartite graph with "black" vertices
, "white" vertices 
, and an edge between 
and 
iff 
(Coxeter 1950, Pisanski and Randić 2000).
The following table summarizes the Levi graphs of some common configurations.
Dual configurations have the same incidence graph, but with the roles of the white and black vertices interchanged.
