منابع مشابه
Conflict-free connection of trees
An edge-colored graph G is conflict-free connected if, between each pair of distinct vertices, there exists a path containing a color used on exactly one of its edges. The conflict-free connection number of a connected graph G, denoted by cfc(G), is defined as the smallest number of colors that are required in order to make G conflict-free connected. A coloring of vertices of a hypergraph H = (...
متن کاملMinimal Spanning Trees with Conflict Graphs
For the classical minimum spanning tree problem we introduce disjunctive constraints for pairs of edges which can not be both included in the spanning tree at the same time. These constraints are represented by a conflict graph whose vertices correspond to the edges of the original graph. Edges in the conflict graph connect conflicting edges of the original graph. It is shown that the problem b...
متن کاملA conflict between two evolutionary levels in trees.
Due to the lack of germ line segregation in plants, it is possible to consider plant evolution (but not the evolution of most animals) as being composed of two evolutionary levels: 1. Intra-organism, in which the replicating unit is a part of the tree (e.g. a branch), reproduction is asexual, mutations are somatic, and selection operates only upon traits relevant to vegetative growth. 2. Inter-...
متن کاملTrees in Graphs with Conflict Edges or Forbidden Transitions
In a recent paper [Paths, trees and matchings under disjunctive constraints, Darmann et. al., Discr. Appl. Math., 2011] the authors add to a graph G a set of conflicts, i.e. pairs of edges of G that cannot be both in a subgraph of G. They proved hardness results on the problem of constructing minimum spanning trees and maximum matchings containing no conflicts. A forbidden transition is a parti...
متن کاملGene and genome trees conflict at many levels.
Horizontal gene transfer (HGT) plays a significant role in microbial evolution. It can accelerate the adaptation of an organism, it can generate new metabolic pathways and it can completely remodel an organism's genome. We examine 27 closely related genomes from the YESS group of gamma proteobacteria and a variety of four-taxon datasets from a diverse range of prokaryotes in order to explore th...
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ژورنال
عنوان ژورنال: Diversity and Distributions
سال: 2001
ISSN: 1366-9516
DOI: 10.1111/j.1472-4642.2001.100-7.x