In this paper the first BSTS in which the upper chromatic number is different from the lower chromatic number is determined. It is a BSTS(19) and its order is the lowest for which this propertyâ€¦ (More)

A Steiner triple system of order v (briefly STS(v)) is a pair (X, B) where X is a v-set and B is a collection of 3-subset of X (called triple) such that every pair of distinct elements of X belongsâ€¦ (More)

In this paper the triangle intersection problem for S(2, 4, v) designs is investigated. Let tv = v(v âˆ’ 1)/3 and IT (v) = {0, 1, . . . , tv âˆ’ 30} âˆª {tv âˆ’ 27, tv âˆ’ 24, tv âˆ’ 18, tv}. Let JT (v) = {s|â€¦ (More)

A mixed hypergraph is characterized by the fact that it possesses C-edges as well as D-edges. In a colouring of a mixed hypergraph, every C-edge has at least two vertices of the same colour and everyâ€¦ (More)