Non-regular square bipartite designs
This paper gives a classification of a new type of non-regular bipartite design generalizing most of the existing results. The case dealt with is a nonregular \((d,\lambda)\) square bipartite design \((A,B)\), \(A^TB=\lambda +\text{diag}(d)\), \(d\) having full support and \(\forall i\neq j\), \(a_{i.} \cdot b_{j.}\geq\lambda\). Then \((A,B)\) is a degenerate projective plane design or is one of 5 special types. It is also proved that this generalizes various previous classifications.
scientific article; zbMATH DE number 1760973
scientific article