O Hadamardově determinantu
O jistých rovinných konfiguracích obsahujících , a -body a konfiguracích singulárních
O počtu tříd silně ekvivalentních incidenčních matic
Obecné konečné geometrie
Odd cycles and a class of facets of the axial 3-index assignment polytope
On 2-ranks of Steiner triple systems.
On 3-harness weaving: cataloging designs generated by fundamental blocks having distinct rows and columns.
On a characterization of symmetric balanced incomplete block designs
All the symmetric balanced incomplete block (SBIB) designs have been characterized and a new generalized expression on parameters of SBIB designs has been obtained. The parameter b has been formulated in a different way which is denoted by bi, i = 1, 2, 3, associating with the types of the SBIB design Di. The parameters of all the designs obtained through this representation have been tabulated while corresponding them with the suitable formulae for the number ofblocks bi and the expression Si for...
On a class of commutative groupoids determined by their associativity triples
Let be a commutative groupoid such that ; ; or . Then is determined uniquely up to isomorphism and if it is finite, then for an integer .
On a class of distributive Steiner quasigroups
On a class of partial -spreads of arising from scrolls.
On a combinatorical problem of K. Zarankiewicz
On a conjecture concerning dyadic oriented matroids.
On a conjecture of the semigroup of fully indecomposable relations
On a construction of regular Hadamard matrices
We give a construction for regular Hadamard matrices of order where is the order of a Hadamard matrix and is the order of a regular Hadamard matrix. The construction can be used to construct regular Hadamard matrices with special properties and includes several constructions which have been given previously. In the final section we consider the case in more detail.
On a covering problem of Mullin and Stanton for binary matroids.
On a discrete version of the antipodal theorem
The classical theorem of Borsuk and Ulam [2] says that for any continuous mapping there exists a point such that f(-x) = f(x). In this note a discrete version of the antipodal theorem is proved in which is replaced by the set of vertices of a high-dimensional cube equipped with Hamming’s metric. In place of equality we obtain some optimal estimates of which were previously known (as far as the author knows) only for f linear (cf. [1]).
On a distance of groups and Latin squares
On a generalization of the matroid
On a planar construction of quasigroups