Titlebook: Mathematical Foundations of Computer Science 2008; 33rd International S Edward Ochmański,Jerzy Tyszkiewicz Conference proceedings 2008 Spri

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Optimizing Conjunctive Queries over Trees Using Schema Informationquery containment and validity are 2EXPTIME-complete w.r.t. a schema (DTD or Relax NG). Furthermore, we show that satisfiability for conjunctive queries w.r.t. a schema can be decided in NP. The problem is NP-hard already for queries using only one kind of axis. Finally, we consider conjunctive quer

漂泊

Clustering with Partial Information, such that the editing cost is minimized. The . problem seeks to partition the edges of a given graph into edge-disjoint cliques, such that the number of cliques is minimized. Both problems are known to be NP-hard, and they have been previously studied with respect to approximation and fixed parame

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Processes

On the Shortest Linear Straight-Line Program for Computing Linear Formsof linear forms. SLP is shown to be NP-hard. Furthermore, a special case of the corresponding decision problem is shown to be . SNP-Complete..Algorithms producing cancellation-free straight-line programs, those in which there is never any cancellation of variables in GF(2), have been proposed for ci

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Flip Algorithm for Segment Triangulationstes, edges, and faces. The set of faces is a maximal set of disjoint triangles such that the vertices of each triangle are on three distinct sites. The segment Delaunay triangulation of . is the segment triangulation of . whose faces are inscribable in circles whose interiors do not intersect .. It

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neuron

A 6/5-Approximation Algorithm for the Maximum 3-Cover Problemcollection of at most . sets whose union contains the maximum number of elements from the ground set. This is a fundamental combinatorial optimization problem with applications to resource allocation. We study the simplest APX-hard variant of the problem where all sets are of size at most 3 and we p

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發(fā)生

Impugn

A Decision Problem for Ultimately Periodic Sets in Non-standard Numeration Systems} without two consecutive 1. Given a set . of integers such that the language of their greedy representations in this system is accepted by a finite automaton, we consider the problem of deciding whether or not . is a finite union of arithmetic progressions. We obtain a decision procedure under some