On $\lambda$ -fold coverings with maximum block size four for $\lambda\ge 6$

Grannell, M. J.; Griggs, T. S. and Stanton, RG (2004). On $\lambda$ -fold coverings with maximum block size four for $\lambda\ge 6$ . Utilitas Mathematica, 66, pp. 221–230.

Abstract

The minimum number of blocks having maximum size precisely four that are required to cover, exactly $\lambda$ times, all pairs of elements from a set of cardinality $v$ is denoted by $g_{\lambda}^{(4)}(v)$ . We present a complete solution to this problem for $\lambda\ge 6$ .