Trees related to realizations of distance matrices
نویسندگان
چکیده
منابع مشابه
The Distance Matrices of Some Graphs Related to Wheel Graphs
A simple graph G = (V, E) consists of V, a nonempty set of vertices, and E, a set of unordered pairs of distinct elements of V called edges. All graphs considered here are simple and connected. LetG be a simple connected graph with vertex set V(G) and edge set E(G).The distance between two vertices u, V ∈ V(G) is denoted by d uV and is defined as the length of the shortest path between u and V ...
متن کاملA note on tree realizations of matrices
It is well known that each tree metric M has a unique realization as a tree, and that this realization minimizes the total length of the edges among all other realizations of M . We extend this result to the class of symmetric matrices M with zero diagonal, positive entries, and such that mij +mkl ≤ max{mik +mjl,mil +mjk} for all distinct i, j, k, l.
متن کاملGraphic Realizations of Joint-Degree Matrices
In this paper we introduce extensions and modifications of the classical degree sequence graphic realization problem studied by Erdős-Gallai and Havel-Hakimi, as well as of the corresponding connected graphic realization version. We define the joint-degree matrix graphic (resp. connected graphic) realization problem, where in addition to the degree sequence, the exact number of desired edges be...
متن کاملThe triangles method to build X-trees from incomplete distance matrices
A method to infer X-trees (valued trees having X as set of leaves) from incomplete distance arrays (where some entries are uncertain or unknown) is described. It allows us to build an unrooted tree using only 2n-3 distance values between the n elements of X, if they fulfill some explicit conditions. This construction is based on the mapping between X-tree and a weighted generalized 2-tree spann...
متن کاملOptimal algorithms for computing the Robinson and Foulds topologic distance between two trees and the strict consensus trees of k trees given their distance matrices
It has been postulated that existing species have been linked in the past in a way that can be described using an additive tree structure. Any such tree structure reflecting species relationships is associated with a matrix of distances between the species considered and called a distance matrix or a tree metric matrix. A circular order of elements of X corresponds to a circular (clockwise) sca...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 1998
ISSN: 0012-365X
DOI: 10.1016/s0012-365x(98)00081-8