A distribution invariant for association schemes and strongly regular graphs

In an association scheme X with symmetric classes the projections J_i(x) of the points x ? X into the given Eigenspace E_i are considered. In particular the smallest number of points whose projection vectors are strictly on one side of a hyperlane is called the distribution invariant (with respect to E_i) of the association scheme X. Examples are given where the distribution invariants can be calculated, as for the triangular graphs and for all strongly regular graphs with less than 17 points.