ABSTRACT
A pairwise balanced design of index λ is a way of selecting blocks from a set of treatments (support set) such that any two treatments have covalency λ. If there are v treatments and if every block size is a member of some set K of positive integers, the design is designated a PB(v;K; λ). So the parameters consist of two positive integers and one set of positive integers. To avoid trivial differences between designs, block size 1 is not allowed.
