Results 281 to 290 of about 1,675,375 (319)
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Theory in Biosciences, 2010
Darwin saw similarities between the evolution of species and the evolution of languages, and it is now widely accepted that similarities between related languages can often be interpreted in terms of a bifurcating descent history (‘phylogenesis’). Such interpretations are supported when the distributions of shared and unshared traits (for example, in ...
James Steele, Anne Kandler
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Darwin saw similarities between the evolution of species and the evolution of languages, and it is now widely accepted that similarities between related languages can often be interpreted in terms of a bifurcating descent history (‘phylogenesis’). Such interpretations are supported when the distributions of shared and unshared traits (for example, in ...
James Steele, Anne Kandler
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Genome trees and the tree of life
Trends in Genetics, 2002Genome comparisons indicate that horizontal gene transfer and differential gene loss are major evolutionary phenomena that, at least in prokaryotes, involve a large fraction, if not the majority, of genes. The extent of these events casts doubt on the feasibility of constructing a 'Tree of Life', because the trees for different genes often tell ...
Yuri I, Wolf +3 more
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2017
This chapter considers the problem of counting trees. Every connected graph G has a spanning tree, that is, a connected acyclic subgraph containing all the vertices of G. If G has no cycles, it is its own unique spanning tree. If G has cycles, we can locate any cycle and delete one of its edges. Repeat this process until no cycle remains.
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This chapter considers the problem of counting trees. Every connected graph G has a spanning tree, that is, a connected acyclic subgraph containing all the vertices of G. If G has no cycles, it is its own unique spanning tree. If G has cycles, we can locate any cycle and delete one of its edges. Repeat this process until no cycle remains.
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Journal of Symbolic Logic, 1971
This is an attempt to give a survey of recent results concerning trees. The article is an extended version of our talk in Oberwolfach (Schwarzwald) last May; the forests surrounding the Forschungsinstitut turned out to be a good inspiration.A tree is a partially ordered set T = (T, ≤) such that for every x ∈ T, the set = {y ∈ T: y < x} is well ...
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This is an attempt to give a survey of recent results concerning trees. The article is an extended version of our talk in Oberwolfach (Schwarzwald) last May; the forests surrounding the Forschungsinstitut turned out to be a good inspiration.A tree is a partially ordered set T = (T, ≤) such that for every x ∈ T, the set = {y ∈ T: y < x} is well ...
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Molecular Ecology, 1998
The practice of tracking geographical divergence along a phylogenetic tree has added an evolutionary perspective to biogeographic analysis within single species. In spite of the popularity of phylogeography, there is an emerging problem. Recurrent mutation and recombination both create homoplasy, multiple evolutionary occurrences of the same character ...
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The practice of tracking geographical divergence along a phylogenetic tree has added an evolutionary perspective to biogeographic analysis within single species. In spite of the popularity of phylogeography, there is an emerging problem. Recurrent mutation and recombination both create homoplasy, multiple evolutionary occurrences of the same character ...
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Interpreting Tree-to-Tree Queries
2006We establish correspondences between top-down tree building query languages and predicate logics. We consider the expressive power of the query language XQ, a clean core of the practitioner's language XQuery. We show that all queries in XQ with only atomic equality are equivalent to “first-order interpretations”, an analog to first-order logic (FO) in ...
Michael Benedikt, Christoph Koch 0001
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THE TREE-TO-TREE EDITING PROBLEM
International Journal of Pattern Recognition and Artificial Intelligence, 1988This paper describes the computing alogrithms for the tree distance based on the structure preserving mapping. The distance is defined as the minimum sum of the weights of edit operations needed to transform tree Tα to tree Tβ under restriction of the structure preserving mapping.
Eiichi Tanaka, Keiko Tanaka
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Mathematical Programming, 1994
The class of 2-tree graphs is defined inductively as follows: start with a single edge and add nodes by joining them to the two endpoints of an existing edge. Many NP-complete problems on graphs are polynomial when restricted to this class of graphs. In particular, the Steiner Tree problem is linear time solvable on graphs in this class.
François Margot +2 more
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The class of 2-tree graphs is defined inductively as follows: start with a single edge and add nodes by joining them to the two endpoints of an existing edge. Many NP-complete problems on graphs are polynomial when restricted to this class of graphs. In particular, the Steiner Tree problem is linear time solvable on graphs in this class.
François Margot +2 more
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Trees and Tree-Equivalent Graphs
Canadian Journal of Mathematics, 1965As is well known in the theory of graphs a tree is a connected graph without cycles. Many characterizing properties of trees are known (1), for example the cyclomatic number is equal to zero, which is also equal to p — 1, where p is the number of connected components of the graph.
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