Context-sensitive transitive closure operators
نویسندگان
چکیده
منابع مشابه
On the Computation of the Transitive Closure of Relational Operators
Query processing in the presence of recursively defined views usually involves some form of iteration. For example, computing the transitive closure of a tree involves iterating N times, where N is the depth of the tree, each time computing pairs of vertices that are one edge further apart than the pairs produced in the previous iteration. Applying a divide and conquer technique we devise algor...
متن کاملHybrid Transitive Closure Algorithms
We present a new family of hybrid transitive closure algorithms, and present experimental results showing that these algorithms perform better than existing transitive closure algorithms, includmg matrix-based algorithms that divide a matrix into stripes or into square blocks, and graph-based algmtihms. This family of algorithms can be generalized to solve path problems and to solve problems in...
متن کاملTransitive-closure spanners
We define the notion of a transitive-closure spanner of a directed graph. Given a directed graph G = (V,E) and an integer k ≥ 1, a k-transitive-closure-spanner (k-TC-spanner) of G is a directed graph H = (V,EH) that has (1) the same transitive-closure as G and (2) diameter at most k. These spanners were studied implicitly in access control, property testing, and data structures, and properties ...
متن کاملEecient Transitive Closure Computation
We present two new transitive closure algorithms that are based on strong component detection. The algorithms scan the input graph only once without generating partial successor sets for each node. The new algorithms eliminate the redundancy caused by strong components more e ciently than previous transitive closure algorithms. We present statistically sound simulation experiments showing that ...
متن کامل2.1 Transitive Closure
Note that, in some sense, the O(n2) result is optimal if we approach this problem by storing the transitive closure matrix explicitly (we don’t necessarily have to do this, however, to answer queries). This is because in the worst case, an update can modify Ω(n2) edges in the transitive closure. Next are two results for which the product of the bulk update and query times is O(mn), where m is t...
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ژورنال
عنوان ژورنال: Annals of Pure and Applied Logic
سال: 1994
ISSN: 0168-0072
DOI: 10.1016/0168-0072(94)90036-1