Article
Monotone Boolean dualization is in coNP[log2n]
Department of Mathematics, University of Patras, Rhion, West Greece, Greece
Information Processing Letters (Impact Factor: 0.55). 01/2003; 85(1):16. DOI: 10.1016/S00200190(02)003460 Source: CiteSeer
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 "Later, decomposition methods giving rise to trees of polylogarithmic depth were published. In particular, the methods of Kavvadias and Stavropoulos [34] as well as the two methods by Elbassioni in [12] give rise to decomposition trees of polylogarithmic depth. Finally, decomposition methods yielding trees of logarithmic depth were presented by Gaur [17] (see also Gaur and Krishnamurti [18]), and, more recently, by Boros and Makino [4]. "
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ABSTRACT: The monotone duality problem is defined as follows: Given two monotone formulas f and g in iredundant DNF, decide whether f and g are dual. This problem is the same as duality testing for hypergraphs, that is, checking whether a hypergraph H consists of precisely all minimal transversals of a simple hypergraph G. By exploiting a recent problemdecomposition method by Boros and Makino (ICALP 2009), we show that duality testing for hypergraphs, and thus for monotone DNFs, is feasible in DSPACE[log^2 n], i.e., in quadratic logspace. As the monotone duality problem is equivalent to a number of problems in the areas of databases, data mining, and knowledge discovery, the results presented here yield new complexity results for those problems, too. For example, it follows from our results that whenever for a Booleanvalued relation (whose attributes represent items), a number of maximal frequent itemsets and a number of minimal infrequent itemsets are known, then it can be decided in quadratic logspace whether there exist additional frequent or infrequent itemsets. 
 "In pioneering work [22], Fredman and Khachiyan gave an algorithm for solving this problem whose running time is O(n 2 ) + N o(log N) , where N = F + G, thus providing strong evidence that this decision problem is unlikely to be NPhard. Eiter et al. [17] [18], and independently Kavvadias and Stavropoulos [36] [35], used the results of [22] to show that the duality of a pair of monotone Boolean functions can be checked in polynomial time with limited nondeterminism, i.e., with a polylogarithmic number of suitably guessed bits, putting thus the problem in the class co2 P (see e.g., [40] for the definition of this class). Gaur and Krishnamurti [25] gave another algorithm for the equivalent problem of checking if a Boolean function is selfdual (i.e., if f d (x) = f (x)), and showed it to run in time O(N 2 log N+2 ) in general, and in polynomial time on random instances. "
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ABSTRACT: In 1994 Fredman and Khachiyan established the remarkable result that the duality of a pair of monotone Boolean functions, in disjunctive normal forms, can be tested in quasipolynomial time, thus putting the problem, most likely, somewhere between polynomiality and coNPcompleteness. We strengthen this result by showing that the duality testing problem can in fact be solved in polylogarithmic time using a quasipolynomial number of processors (in the PRAM model). While our decomposition technique can be thought of as a generalization of that of Fredman and Khachiyan, it yields stronger bounds on the sequential complexity of the problem in the case when the sizes of f and g are significantly different, and also allows for generating all minimal transversals of a given hypergraph using only polynomial space.Discrete Applied Mathematics 06/2008; 156(11156):21092123. DOI:10.1016/j.dam.2007.05.030 · 0.80 Impact Factor 
 "Hence, Monet and Monet have many applications in such different fields like artificial intelligence and logic [6] [7], computational biology [3], database theory [18], data mining and machine learning [12], mobile communication systems [22], distributed systems [10], and graph theory [13] [16]. The currently best known algorithms for Monet run in quasipolynomial time or use O(log 2 n) nondeterministic bits [8] [9] [14]. "
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ABSTRACT: We consider the problem Monet—given two monotone formulas φ in DNF and ψ in CNF, decide whether they are equivalent. While Monet is probably not coNPhard, it is a long standing open question whether it has a polynomial time algorithm and thus belongs to P. In this paper we examine the parameterized complexity of Monet. We show that Monet is in FPT by giving fixedparameter algorithms for different parameters.Information Processing Letters 08/2007; 103(4103):163167. DOI:10.1016/j.ipl.2007.03.009 · 0.55 Impact Factor