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» Amalgams of Constraint Satisfaction Problems
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DATE
2004
IEEE
175views Hardware» more  DATE 2004»
13 years 11 months ago
Breaking Instance-Independent Symmetries in Exact Graph Coloring
Code optimization and high level synthesis can be posed as constraint satisfaction and optimization problems, such as graph coloring used in register allocation. Graph coloring is...
Arathi Ramani, Fadi A. Aloul, Igor L. Markov, Kare...
PODS
2007
ACM
159views Database» more  PODS 2007»
14 years 7 months ago
Generalized hypertree decompositions: np-hardness and tractable variants
The generalized hypertree width GHW(H) of a hypergraph H is a measure of its cyclicity. Classes of conjunctive queries or constraint satisfaction problems whose associated hypergr...
Georg Gottlob, Thomas Schwentick, Zoltán Mi...
FOCS
2008
IEEE
14 years 1 months ago
Beating the Random Ordering is Hard: Inapproximability of Maximum Acyclic Subgraph
We prove that approximating the Max Acyclic Subgraph problem within a factor better than 1/2 is Unique-Games hard. Specifically, for every constant ε > 0 the following holds:...
Venkatesan Guruswami, Rajsekar Manokaran, Prasad R...
CP
2010
Springer
13 years 5 months ago
The Lattice Structure of Sets of Surjective Hyper-Operations
Abstract. We study the lattice structure of sets (monoids) of surjective hyper-operations on an n-element domain. Through a Galois connection, these monoids form the algebraic coun...
Barnaby Martin
WISEC
2009
ACM
14 years 1 months ago
Towards a theory for securing time synchronization in wireless sensor networks
Time synchronization in highly distributed wireless systems like sensor and ad hoc networks is extremely important in order to maintain a consistent notion of time throughout the ...
Murtuza Jadliwala, Qi Duan, Shambhu J. Upadhyaya, ...