On Strong Tactical Decompositions
Henry J. Beker · Journal of the London Mathematical Society · 1977
If a 2-(v, k, k) design 2) admits a tactical decomposition with d point classes and c block classes then b — v ^ c—d ^ 0, (see [3]). Decompositions for which b+d = v + c are of special interest (see for instance [1]), and are called strong. Any tactical decomposition of a symmetric design is strong. A strong tactical decomposition of a