The algebraic multiplicity of the number zero in the spectrum of a bipartite graph
The Bruhat rank of a binary symmetric staircase pattern
In this work we show that the Bruhat rank of a symmetric (0,1)-matrix of order n with a staircase pattern, total support, and containing In, is at most 2. Several other related questions are also discussed. Some illustrative examples are presented.
The calculation of α-sets of representatives
The check positions of Hamming codes and the construction of a 2EC-AUED code.
The difference matrices of the classes of a Sharma-Kaushik partition
Sharma-Kaushik partitions have been used to define distances between vectors with -coordinates. In this paper, “difference matrices” for the partitioning classes have been introduced and investigated. It has been shown that the difference matrices are circulant and that the entries of a product of matrices is an extended intersection number of a distance scheme. The sum of the entries of each row or columns of the product matrix has been obtained. The algebra of matrices generated by the difference...
The maximum number of odd submatrices in -matrices.
The Moore-Penrose inverse of a free matrix.
Thin Lehman matrices and their graphs.
Two improvements of a result concerning a problem of K. Zarankiewicz
Two-level Cretan matrices constructed using SBIBD
Two-level Cretan matrices are orthogonal matrices with two elements, x and y. At least one element per row and column is 1 and the other element has modulus ≤ 1. These have been studied in the Russian literature for applications in image processing and compression. Cretan matrices have been found by both mathematical and computational methods but this paper concentrates on mathematical solutions for the first time. We give, for the first time, families of Cretan matrices constructed using the incidence...
Über die Existenz von Indizenstrukturen mit Regularitätsbedingungen.
Un algorithme pour l'obtention d'une chaîne Hamiltonienne en partant de l'arbre minimal d'un graphe
Uniqueness of the Rank Polynomials of Point Stable Designs.
When does the inverse have the same sign pattern as the transpose?
By a sign pattern (matrix) we mean an array whose entries are from the set . The sign patterns for which every real matrix with sign pattern has the property that its inverse has sign pattern are characterized. Sign patterns for which some real matrix with sign pattern has that property are investigated. Some fundamental results as well as constructions concerning such sign pattern matrices are provided. The relation between these sign patterns and the sign patterns of orthogonal matrices...
Zur Hermite-Birkhoff-Interpolation: DMS-Inzidenzmatrizen.
Zur Konstruktion von t-Plänen nach der Allgemeinen Differenzenmethode.
Максимальная глубина произвольных классов(0,1)-матриц и некоторые ее применения
О максимальной глубине одного класса (0,1)-матриц
О некоторых комбинаторных свойствах (0,1)-матриц