87 research outputs found

    0-1 Integer Linear Programming with a Linear Number of Constraints

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    We give an exact algorithm for the 0-1 Integer Linear Programming problem with a linear number of constraints that improves over exhaustive search by an exponential factor. Specifically, our algorithm runs in time 2(1poly(1/c))n2^{(1-\text{poly}(1/c))n} where n is the number of variables and cn is the number of constraints. The key idea for the algorithm is a reduction to the Vector Domination problem and a new algorithm for that subproblem

    Fixed parameter tractability of crossing minimization of almost-trees

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    We investigate exact crossing minimization for graphs that differ from trees by a small number of additional edges, for several variants of the crossing minimization problem. In particular, we provide fixed parameter tractable algorithms for the 1-page book crossing number, the 2-page book crossing number, and the minimum number of crossed edges in 1-page and 2-page book drawings.Comment: Graph Drawing 201

    On Exact Algorithms for Permutation CSP

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    In the Permutation Constraint Satisfaction Problem (Permutation CSP) we are given a set of variables VV and a set of constraints C, in which constraints are tuples of elements of V. The goal is to find a total ordering of the variables, π :V[1,...,V]\pi\ : V \rightarrow [1,...,|V|], which satisfies as many constraints as possible. A constraint (v1,v2,...,vk)(v_1,v_2,...,v_k) is satisfied by an ordering π\pi when π(v1)<π(v2)<...<π(vk)\pi(v_1)<\pi(v_2)<...<\pi(v_k). An instance has arity kk if all the constraints involve at most kk elements. This problem expresses a variety of permutation problems including {\sc Feedback Arc Set} and {\sc Betweenness} problems. A naive algorithm, listing all the n!n! permutations, requires 2O(nlogn)2^{O(n\log{n})} time. Interestingly, {\sc Permutation CSP} for arity 2 or 3 can be solved by Held-Karp type algorithms in time O(2n)O^*(2^n), but no algorithm is known for arity at least 4 with running time significantly better than 2O(nlogn)2^{O(n\log{n})}. In this paper we resolve the gap by showing that {\sc Arity 4 Permutation CSP} cannot be solved in time 2o(nlogn)2^{o(n\log{n})} unless ETH fails

    Lightsolver challenges a leading deep learning solver for Max-2-SAT problems

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    Maximum 2-satisfiability (MAX-2-SAT) is a type of combinatorial decision problem that is known to be NP-hard. In this paper, we compare LightSolver's quantum-inspired algorithm to a leading deep-learning solver for the MAX-2-SAT problem. Experiments on benchmark data sets show that LightSolver achieves significantly smaller time-to-optimal-solution compared to a state-of-the-art deep-learning algorithm, where the gain in performance tends to increase with the problem size
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