Zobrazeno 1 - 10
of 28
pro vyhledávání: '"Victor Neumann"'
Autor:
Bernardo Llano, Victor Neumann-Lara
Publikováno v:
Discrete Mathematics. 308:6056-6063
We say that a tournament is tight if for every proper 3-coloring of its vertex set there is a directed cyclic triangle whose vertices have different colors. In this paper, we prove that all circulant tournaments with a prime number p≥3 of vertices
Publikováno v:
Discrete Mathematics. 308(16):3441-3448
The neighbourhood heterochromatic numbernh"c(G) of a non-empty graph G is the smallest integer l such that for every colouring of G with exactly l colours, G contains a vertex all of whose neighbours have different colours. We prove that lim"n"->"~(n
Publikováno v:
Graphs and Combinatorics. 21:343-354
Let h(n,p) be the minimum integer such that every edge-colouring of the complete graph of order n, using exactly h(n,p) colours, produces at least one cycle of order p having all its edges of different colours. In this paper the value of h(n,p) is de
Publikováno v:
Graphs and Combinatorics. 20:223-231
For any set P of n points in general position in the plane there is a convex decomposition of P with at most * elements. Moreover, any minimal convex decomposition of such a set P has at most * elements, where k is the number of points in the boundar
Publikováno v:
Discrete Mathematics. 282(1-3):183-191
The clique graph of a graph G is the intersection graph K(G) of the (maximal) cliques of G. The iterated clique graphs Kn(G) are defined by K0(G)=G and Ki(G)=K(Ki−1(G)), i>0 and K is the clique operator. A cograph is a graph with no induced subgrap
Publikováno v:
Graphs and Combinatorics. 19:533-536
Let G=(V(G),E(G)) be a multigraph with multiple loops allowed, and V 0⊆V(G). We define h(G,V 0) to be the minimum integer k such that for every edge-colouring of G using exactly k colours, all the edges incident with some vertex in V 0 receive diff
Publikováno v:
Discrete Mathematics. 271:303-310
For a set C of cycles of a connected graph G we define T(G,C) as the graph with one vertex for each spanning tree of G, in which two trees R and S are adjacent if R∪S contains exactly one cycle and this cycle lies in C. We give necessary conditions
Publikováno v:
Discrete Mathematics. 258:123-135
We study the dynamical behaviour of surface triangulations under the iterated application of the clique graph operator k, which transforms each graph G into the intersection graph kG of its (maximal) cliques. A graph G is said to be k-divergent if th
Publikováno v:
Discrete Mathematics. :633-636
For every 2-connected graph G with circumference c there are c bonds B 1 , B 2 , …, B v of G such that every edge of G lies in at least two of them.
Autor:
Victor Neumann-Lara, F. Larrión
Publikováno v:
Discrete Mathematics. :491-501
The clique graph kG of a graph G is the intersection graph of the family of all maximal complete subgraphs of G . The iterated clique graphs k n G are defined by k 0 G = G and k n +1 G = kk n G . A graph G is said to be k -divergent if | V ( k n G )|