Given a distance-regular graph G with integers b_i, c_i, i = 0, ..., d such that for any two vertices x, y element G at distance i = d(x, y), there are exactly c_i neighbors of y element G_(i - 1)(x) and b_i neighbors of y element G_(i + 1)(x), the sequence ι(γ) = {b_0, b_1, ..., b_(d - 1) ;c_1, ..., c_d} is called the intersection array of G. A similar type of intersection array can also be defined for a distance-transitive graph. A distance-regular graph with global parameters [[c_0, a_0, b_0], [c_1, a_1, b_1], [c_2, a_2, b_2], [c_3, a_3, b_3], [c_4, a_4, b_4]] has intersection array {b_0, b_1, b_2, b_3 ;c_1, c_2, c_3, c_4}.

distance-regular graph | distance-transitive graph | global parameters