A maximum ($v,G,\lambda$)-$PD$ and a minimum ($v,G,\lambda$)-$CD$ are studied for 2 graphs of 6 vertices and 7 edges. By means of ``difference method" and ``holey graph design'', we obtain the result: there exists a $(v,G_i,\lambda)$-$OPD$ $(OCD)$ for $v\equiv 2,3,4,5,6~({\rm mod}\,~7)$, $\lambda \geq 1,~i=1,2$. |