human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "satisfiability and computing van der waerden numbers"
  Abstract: In this paper we bring together the areas of combinatorics and propositional satisfiability. Many combinatorial theorems establish, often constructively, the existence of positive integer functions, without actually providing their closed algebraic form or tight lower and upper bounds. The area of Ramsey theory is especially rich in such results. Using the problem of computing van der Waerden numbers as an example, we show that these problems can be represented by parameterized propositional theories in such a way that decisions concerning their satisfiability determine the numbers (function) in question. We show that by using general-purpose complete and local-search techniques for testing propositional satisfiability, this approach becomes effective -- competitive with specialized approaches. By following it, we were able to obtain several new results pertaining to the problem of computing van der Waerden numbers. We also note that due to their properties, especially their structural simplicity and computational hardness, propositional theories that arise in this research can be of use in development, testing and benchmarking of SAT solvers.

Connected through hyperedge HE-1 (induced by source paper "the sat cas method for combinatorial search with applications to best matrices"):
  with members:
    - "applying computer algebra systems with sat solvers to the williamson conjecture"
    - "complex golay pairs up to length 28 a search via computer algebra and programmatic sat"
    - "enumeration of complex golay pairs via programmatic sat"
    - "a sat cas approach to finding good matrices new examples and counterexamples"
    - "schur number five"
    - "solving and verifying the boolean pythagorean triples problem via cube and conquer"
    - "green tao numbers and sat"

Connected through hyperedge HE-2 (induced by source paper "solving and verifying the boolean pythagorean triples problem via cube and conquer"):
  with members:
    - "symbiosis of search and heuristics for random 3 sat"

Connected through hyperedge HE-3 (induced by source paper "computing the ramsey number r 4 3 3 using abstraction and symmetry breaking"):
  with members:
    - "boolean equi propagation for concise and efficient sat encodings of combinatorial problems"
    - "diamond free degree sequences"

Connected through hyperedge HE-4 (induced by source paper "green tao numbers and sat"):
  with members:
    - "constraint satisfaction problems in clausal form"
    - "survey propagation an algorithm for satisfiability"

Connected through hyperedge HE-5 (induced by source paper "wsat cc a fast local search asp solver"):
  with members:
    - "local search techniques for propositional logic extended with cardinality constraints"
    - "propositional satisfiability in answer set programming"

Question: Please tell me which class the center node belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.LO(Logic in Computer Science)