Class-uniformly resolvable group divisible structures. II: Frames.
Cliques and Claws in Edge-transitive Strongly Regular Graphs.
Closure conditions of commutativity
There are investigated some closure conditions of Thomsen type in 3-webs which gurantee that at least one of coordinatizing quasigroups of a given 3-web is commutative.
Coalescing Fiedler and core vertices
The nullity of a graph is the multiplicity of zero as an eigenvalue in the spectrum of its adjacency matrix. From the interlacing theorem, derived from Cauchy’s inequalities for matrices, a vertex of a graph can be a core vertex if, on deleting the vertex, the nullity decreases, or a Fiedler vertex, otherwise. We adopt a graph theoretical approach to determine conditions required for the identification of a pair of prescribed types of root vertices of two graphs to form a cut-vertex of unique...
Codes, lattices, and Steiner systems.
Coherent configurations I
Collineations and Extensions of Translation Nets.
Collineations of the Subiaco generalized quadrangles.
Colouring 4-cycle systems with specified block colour patterns: The case of embedding -designs.
Combinatorial approaches and conjectures for 2-divisibility problems concerning domino tilings of polyominoes.
Combinatorial Geometries Representable over GF(3) and GF(q). I. The Number of Points.
Combinatorial lemmas for polyhedrons
We formulate general boundary conditions for a labelling to assure the existence of a balanced n-simplex in a triangulated polyhedron. Furthermore we prove a Knaster-Kuratowski-Mazurkiewicz type theorem for polyhedrons and generalize some theorems of Ichiishi and Idzik. We also formulate a necessary condition for a continuous function defined on a polyhedron to be an onto function.
Combinatorial lemmas for polyhedrons I
We formulate general boundary conditions for a labelling of vertices of a triangulation of a polyhedron by vectors to assure the existence of a balanced simplex. The condition is not for each vertex separately, but for a set of vertices of each boundary simplex. This allows us to formulate a theorem, which is more general than the Sperner lemma and theorems of Shapley; Idzik and Junosza-Szaniawski; van der Laan, Talman and Yang. A generalization of the Poincaré-Miranda theorem is also derived.
Combinatorial Models for the Finite-Dimensional Grassmannians.
Combinatorial Obstructions to the Lifting of Weaving Diagrams.
Combinatorial Structures in Loops.
Common Transversals Of Finite Families
Common transversals of finite families.
Commutative subloop-free loops
We describe, in a constructive way, a family of commutative loops of odd order, , which have no nontrivial subloops and whose multiplication group is isomorphic to the alternating group .
Compatible factorizations and three-fold triple systems.