On cardinalities of row spaces of Boolean matrices.
On Difference Matrices, Resolvable Transversal Designs and Generalized Hadamard Matrices.
On idempotent binary relations on a finite set
On large random almost euclidean bases.
On powers of non-negative matrices
On special structure of graphs having the maximal eigenvalue greater than two.
On Spectral Structure Of Graphs Having The Maximal Eigenvalue Not Grater Than Two
On Supplementary Difference Sets.
On the combinatorial structure of -matrices representing nonobtuse simplices
A -simplex is the convex hull of affinely independent vertices of the unit -cube . It is nonobtuse if none of its dihedral angles is obtuse, and acute if additionally none of them is right. Acute -simplices in can be represented by -matrices of size whose Gramians have an inverse that is strictly diagonally dominant, with negative off-diagonal entries. In this paper, we will prove that the positive part of the transposed inverse of is doubly stochastic and has the same support...
On the Construction and Characterisation of a Class of Designs.
On the existence of (196,91,42) Hadamard difference sets
On the exponent of -regular primitive matrices.
On the number of possible row and column sums of -matrices.
On the semigroup of binary relations on a finite set
On the twin designs with the Ionin-type parameters.
On the volume of the polytope of doubly stochastic matrices.
Orthogonal designs II.
Overlapping Pfaffians.
Parallel Class Intersection Matrices of Orthogonal Resolutions
This work was partially supported by the Bulgarian National Science Fund under Contract No MM 1405. Part of the results were announced at the Fifth International Workshop on Optimal Codes and Related Topics (OCRT), White Lagoon, June 2007, BulgariaParallel class intersection matrices (PCIMs) have been defined and used in [6], [14], [15] for the classification of resolvable designs with several parameter sets. Resolutions which have orthogonal resolutions (RORs) have been classified in [19] for designs...
Permanents – a concise survey. (Permanenten – Ein kurzer Überblick.)