A central point of a graph is a graph vertex 
whose graph eccentricity equals the graph
radius. The set of all central points is called the graph center.
In analytic number theory, the central point of an L-function is the point fixed by the
symmetry in its functional
equation. For a functional equation relating
and 
, the central point is 
. For the classical normalization of an elliptic
curve L-function relating 
and 
, it is 
.
