Isols and balanced block designs with
Latent roots and off-diagonal elements of the association matrix in PBIB designs and the number of associate classes
Matematika za karetní hrou dobble
V tomto článku se zabýváme návazností populární karetní hry dobble na kombinatorické struktury. Ukazujeme, že existence dokonalých balíčků karet souvisí s existencí konečných projektivních rovin a systémů ortogonálních latinských čtverců. Dále pomocí obecnější struktury, blokových schémat, diskutujeme možnosti vytváření balíčků karet pro hry s modifikovanými pravidly. Výklad, příklady i přílohy jsou uzpůsobeny tomu, aby si čtenář mohl relativně jednoduše vytvořit vlastní karetní systémy.
Maximal sum-free sets and block designs
Multiplicative cones- a family of three eigenvalue graphs.
Mutually disjoint Steiner systems (5, 8, 24) and 5-(24,12,48) designs.
New Binary Extremal Self-Dual Codes of Lengths 50 and 52
* This work was partially supported by the Bulgarian National Science Fund under Contract No. MM – 503/1995.New extremal binary self-dual codes of lengths 50 and 52 are constructed. Some of them are the first known codes with such weight enumerators. The structure of their automorphisms groups are shown.
New infinite families of 3-designs from algebraic curves of higher genus over finite fields.
New optimal constant weight codes.
New regular partial difference sets and strongly regular graphs with parameters and .
New Symmetric (61,16,4) Designs Invariant Under the Dihedral Group of Order 10
∗ This work has been partially supported by the Bulgarian NSF under Contract No. I-506/1995.In this note we construct five new symmetric 2-(61,16,4) designs invariant under the dihedral group of order 10. As a by-product we obtain 25 new residual 2-(45,12,4) designs. The automorphism groups of all new designs are computed.
New symmetric designs from regular Hadamard matrices.
Non-Existence of Steiner Systems of Type S (d - 1, d, 2d).
Nonisomorphic Steiner Triple System.
Non-isomorphic Steiner triples with subsystems
Note on Symmetric Designs and Projective Spaces.
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 distributive Steiner quasigroups
On an algorithm for a double-resolvability test.
On independent sets