Finding a homotopy base for directed paths in an acyclic graph
نویسندگان
چکیده
منابع مشابه
Finding Disjoint Paths on Directed Acyclic Graphs
Given k + 1 pairs of vertices (s1, s2), (u1, v1), . . . , (uk, vk) of a directed acyclic graph, we show that a modified version of a data structure of Suurballe and Tarjan can output, for each pair (ul, vl) with 1 ≤ l ≤ k, a tuple (s1, t1, s2, t2) with {t1, t2} = {ul, vl} in constant time such that there are two disjoint paths p1, from s1 to t1, and p2, from s2 to t2, if such a tuple exists. Di...
متن کاملFINDING k PARTIALLY DISJOINT PATHS IN A DIRECTED PLANAR GRAPH
The partially disjoint paths problem is: given: a directed graph, vertices r1, s1, . . . , rk, sk, and a set F of pairs {i, j} from {1, . . . , k}, find: for each i = 1, . . . , k a directed ri − si path Pi such that if {i, j} ∈ F then Pi and Pj are disjoint. We show that for fixed k, this problem is solvable in polynomial time if the directed graph is planar. More generally, the problem is sol...
متن کاملFinding k Disjoint Paths in a Directed Planar Graph
We show that for each fixed k, the problem of finding k pairwise vertex-disjoint directed paths between given pairs of terminals in a directed planar graph is solvable in polynomial time.
متن کاملFinding Community Base on Web Graph Clustering
Search Pointers organize the main part of the application on the Internet. However, because of Information management hardware, high volume of data and word similarities in different fields the most answers to the user s’ questions aren`t correct. So the web graph clustering and cluster placement in corresponding answers helps user to achieve his or her intended results. Community (web communit...
متن کاملAnalyzing Directed Acyclic Graph Recombination
This work studies the edge-based representation of directed acyclic graphs, as well as the properties of recombination operators working on it. It is shown that this representation is not separable, and the structure of the basic information units that must be processed in order to maintain feasibility of the solutions is described. As an experimental analysis indicates, a recombination operato...
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 Applied Mathematics
سال: 1987
ISSN: 0166-218X
DOI: 10.1016/0166-218x(87)90010-2