Circulants and the chromatic index of Steiner triple systems
Circulants and the factorization of the Fibonacci–like numbers
Several authors gave various factorizations of the Fibonacci and Lucas numbers. The relations are derived with the help of connections between determinants of tridiagonal matrices and the Fibonacci and Lucas numbers using the Chebyshev polynomials. In this paper some results on factorizations of the Fibonacci–like numbers and their squares are given. We find the factorizations using the circulant matrices, their determinants and eigenvalues.
Circular binary strings without zigzags.
Circular chromatic index of generalized Blanuša snarks.
Circular chromatic number of planar graphs of large odd girth.
Circular degree choosability.
Circular digraph walks, -balanced strings, lattice paths and Chebychev polynomials.
Circular distance in directed graphs
Circular distance between two vertices , of a strongly connected directed graph is the sum , where is the usual distance in digraphs. Its basic properties are studied.
Circularity of graphs and continua: topology
Class reconstruction numbers of unicyclic graphs
Classes of graphs definable by graph algebra identities or quasi-identities
Classes of Graphs Which Approximate the Complete Euclidean Graph.
Classes of graphs with restricted interval models.
Classes of hypergraphs with sum number one
A hypergraph ℋ is a sum hypergraph iff there are a finite S ⊆ ℕ⁺ and d̲,d̅ ∈ ℕ⁺ with 1 < d̲ < d̅ such that ℋ is isomorphic to the hypergraph where V = S and . For an arbitrary hypergraph ℋ the sum number(ℋ ) is defined to be the minimum number of isolatedvertices such that is a sum hypergraph. For graphs it is known that cycles Cₙ and wheels Wₙ have sum numbersgreater than one. Generalizing these graphs we prove for the hypergraphs ₙ and ₙ that under a certain condition for the edgecardinalities...
Classification of bijections between 321- and 132-avoiding permutations.
Classification of flocks of the quadratic cone over fields of order at most 29.
Classification of generalized Hadamard matrices and quaternary Hermitian self-dual codes of length 18.
Classification of Maximal Optical Orthogonal Codes of Weight 3 and Small Lengths
Dedicated to the memory of the late professor Stefan Dodunekov on the occasion of his 70th anniversary. We classify up to multiplier equivalence maximal (v, 3, 1) optical orthogonal codes (OOCs) with v ≤ 61 and maximal (v, 3, 2, 1) OOCs with v ≤ 99. There is a one-to-one correspondence between maximal (v, 3, 1) OOCs, maximal cyclic binary constant weight codes of weight 3 and minimum dis tance 4, (v, 3; ⌊(v − 1)/6⌋) difference packings, and maximal (v, 3, 1) binary cyclically permutable constant...
Classification of -dipoles on nonorientable surfaces.
Classification of rings with toroidal Jacobson graph
Let be a commutative ring with nonzero identity and the Jacobson radical of . The Jacobson graph of , denoted by , is defined as the graph with vertex set such that two distinct vertices and are adjacent if and only if is not a unit of . The genus of a simple graph is the smallest nonnegative integer such that can be embedded into an orientable surface . In this paper, we investigate the genus number of the compact Riemann surface in which can be embedded and explicitly...