Correspondence between two antimatroid algorithmic characterizations.
Correspondences between the different types of bijections between the symmetric group and the valued Motzkin paths. (Correspondances entre les différents types de bijections entre le groupe symétrique et les chemins de Motzkin valués.)
Corrigendum: A note on self-conjugate -color partitions.
Corrigendum to “Congruences for certain binomial sums”
Theorem 1 of J.-J. Lee, Congruences for certain binomial sums. Czech. Math. J. 63 (2013), 65–71, is incorrect as it stands. We correct this here. The final result is changed, but the essential idea of above mentioned paper remains valid.
Corrigendum to the paper "Generalized Eulerian numbers: combinatorial applications".
Cospectral graphs on 12 vertices.
Cospectral Graphs With Least Eigenvalue at Least -2
Cotas inferiores para el QAP-árbol.
El QAP-Arbol es un caso especial del problema de asignación cuadrática en que los flujos distintos de cero forman un árbol. No se requiere ninguna condición para la matriz de distancias. En este artículo presentamos una formulación del QAP-Arbol como un problema de programación lineal entera. Basándonos en esta formulación hemos construido cuatro relajaciones lagrangianas distintas que nos permiten obtener una serie de cotas inferiores para este problema. Para resolver una de estas relajaciones,...
Countable 1-transitive coloured linear orderings II
This paper gives a structure theorem for the class of countable 1-transitive coloured linear orderings for a countably infinite colour set, concluding the work begun in [1]. There we gave a complete classification of these orders for finite colour sets, of which there are ℵ₁. For infinite colour sets, the details are considerably more complicated, but many features from [1] occur here too, in more marked form, principally the use (now essential it seems) of coding trees, as a means of describing...
Countable homogeneous coloured partial orders [Book]
Countable splitting graphs
A graph is called splitting if there is a 0-1 labelling of its vertices such that for every infinite set C of natural numbers there is a sequence of labels along a 1-way infinite path in the graph whose restriction to C is not eventually constant. We characterize the countable splitting graphs as those containing a subgraph of one of three simple types.
Counterexample to a conjecture on the structure of bipartite partitionable graphs
A graph G is called a prism fixer if γ(G×K₂) = γ(G), where γ(G) denotes the domination number of G. A symmetric γ-set of G is a minimum dominating set D which admits a partition D = D₁∪ D₂ such that , i,j = 1,2, i ≠ j. It is known that G is a prism fixer if and only if G has a symmetric γ-set. Hartnell and Rall [On dominating the Cartesian product of a graph and K₂, Discuss. Math. Graph Theory 24 (2004), 389-402] conjectured that if G is a connected, bipartite graph such that V(G) can be partitioned...
Counterexamples for properties of line graphs of graphs of diameter two
Counterexamples to Hedetniemi's conjecture and infinite Boolean lattices
We prove that for any , there exists an infinite family of graphs such that for all and for all . These counterexamples to Hedetniemi’s conjecture show that the Boolean lattice of exponential graphs with as a base is infinite for .
Counterexamples to the Neggers-Stanley conjecture.
Counting 1324, 4231-avoiding permutations.
Counting 1324-avoiding permutations.
Counting abelian squares.
Counting and selecting at random bipartite graphs with fixed degrees
Counting biorders.