Covers of digraphs
Coxeter polynomials of Salem trees
We compute the Coxeter polynomial of a family of Salem trees, and also the limit of the spectral radii of their Coxeter transformations as the number of their vertices tends to infinity. We also prove that if z is a root of multiplicities for the Coxeter polynomials of the trees respectively, then z is a root for the Coxeter polynomial of their join, of multiplicity at least where .
Coxeter-like complexes.
Cranks and t-cores.
Criteria for of the existence of uniquely partitionable graphs with respect to additive induced-hereditary properties
Let ₁,₂,...,ₙ be graph properties, a graph G is said to be uniquely (₁,₂, ...,ₙ)-partitionable if there is exactly one (unordered) partition V₁,V₂,...,Vₙ of V(G) such that for i = 1,2,...,n. We prove that for additive and induced-hereditary properties uniquely (₁,₂,...,ₙ)-partitionable graphs exist if and only if and are either coprime or equal irreducible properties of graphs for every i ≠ j, i,j ∈ 1,2,...,n.
Criteria for shellable multicomplexes.
Critical Graphs for R(P n , P m ) and the Star-Critical Ramsey Number for Paths
The graph Ramsey number R(G,H) is the smallest integer r such that every 2-coloring of the edges of Kr contains either a red copy of G or a blue copy of H. The star-critical Ramsey number r∗(G,H) is the smallest integer k such that every 2-coloring of the edges of Kr − K1,r−1−k contains either a red copy of G or a blue copy of H. We will classify the critical graphs, 2-colorings of the complete graph on R(G,H) − 1 vertices with no red G or blue H, for the path-path Ramsey number. This classification...
Critical sets in back circulant latin squares.
Critical subgraphs of a random graph.
Criticality concepts in geodetic graphs
Criticality of Switching Classes of Reversible 2-Structures Labeled by an Abelian Group
Let V be a finite vertex set and let (, +) be a finite abelian group. An -labeled and reversible 2-structure defined on V is a function g : (V × V) (v, v) : v ∈ V → such that for distinct u, v ∈ V, g(u, v) = −g(v, u). The set of -labeled and reversible 2-structures defined on V is denoted by ℒ(V, ). Given g ∈ ℒ(V, ), a subset X of V is a clan of g if for any x, y ∈ X and v ∈ V X, g(x, v) = g(y, v). For example, ∅, V and v (for v ∈ V) are clans of g, called trivial. An element g of ℒ(V, ) is primitive...
Crooked functions, bent functions, and distance regular graphs.
Crossing numbers and cutwidths.
Crossings and nestings in tangled diagrams.
Crossings, colorings, and cliques.
Crystals of Fock spaces and cyclotomic rational double affine Hecke algebras
We define the -restriction and -induction functors on the category of the cyclotomic rational double affine Hecke algebras. This yields a crystal on the set of isomorphism classes of simple modules, which is isomorphic to the crystal of a Fock space.
Cube tilings as contributions of algebra to geometry.
Cube-Tilings of Rn and Nonlinear Codes.
Cubic Cayley graphs with small diameter.
Cubic edge-transitive graphs of order .