The existence of blocking sets in (v, {2, 4}, 1)-designs is examined. We show that for v â‰¡ 0, 3, 5, 6, 7, 8, 9, 11 (mod 12), blocking sets cannot exist. We prove that for each v â‰¡ 1, 2, 4 (mod 12)â€¦ (More)

A subset S of a group G is said to be a sum-free set if S n (S + S) = Dâ€™ . Such a set is maximal if for every sum-free set TC G, we have 1 T 1 < 1 S I. Here, we generalize this concept, defining aâ€¦ (More)

In this paper we focus on the representation of Steiner trades of volume less than or equal to nine and identify those for which the associated partial latin square can be decomposed into sixâ€¦ (More)

A periodic binary array is said to be sequential if and only if every line of the array is occupied by a given periodic binary sequence or by some cyclic shift or reversal of this sequence. Suchâ€¦ (More)

We consider the construction of several con"gurations, including: â€¢ overlarge sets of 2-(11; 5; 2) designs, that is, partitions of the set of all 5-subsets of a 12-set into 72 2-(11; 5; 2) designs; â€¢â€¦ (More)