On \(\lambda\)-fold Coverings with Maximum Block Size Four for \(\lambda = 3,4\) and \(5\)

M. J. Grannell1, T. S. Griggs1, R. G, Stanton2
1Department of Pure Mathematics The Open University Walton Hall, Milton Keynes, MK7 6AA United Kingdom
2Department of Computer Science University of Manitoba Winnipeg, Manitoba, R3T 2N2 Canada

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 \( v = 3, 4, \) and \( 5 \).

Keywords: pairwise balanced design, perfect covering.