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: "tractable optimization problems through hypergraph based structural restrictions"
  Abstract: Several variants of the Constraint Satisfaction Problem have been proposed and investigated in the literature for modelling those scenarios where solutions are associated with some given costs. Within these frameworks computing an optimal solution is an NP-hard problem in general; yet, when restricted over classes of instances whose constraint interactions can be modelled via (nearly-)acyclic graphs, this problem is known to be solvable in polynomial time. In this paper, larger classes of tractable instances are singled out, by discussing solution approaches based on exploiting hypergraph acyclicity and, more generally, structural decomposition methods, such as (hyper)tree decompositions.

Connected through hyperedge HE-1 (induced by source paper "point width and max csps"):
  with members:
    - "understanding the complexity of sat using knowledge compilation"
    - "constraint solving via fractional edge covers"
    - "the complexity of general valued csps seen from the other side"
    - "a dichotomy theorem for nonuniform csps"
    - "the proof of csp dichotomy conjecture"
    - "the complexity of finite valued csps"
    - "general and fractional hypertree decompositions hard and easy cases"
    - "understanding model counting for beta acyclic cnf formulas"

Connected through hyperedge HE-2 (induced by source paper "a tractable class of binary vcsps via m convex intersection"):
  with members:
    - "discrete convexity in joint winner property"
    - "a dichotomy theorem for nonuniform csps"
    - "the proof of csp dichotomy conjecture"
    - "the complexity of general valued csps"
    - "tractable triangles and cross free convexity in discrete optimisation"
    - "hybrid tractability of valued constraint problems"

Connected through hyperedge HE-3 (induced by source paper "tree projections and constraint optimization problems fixed parameter tractability and parallel algorithms"):
  with members:
    - "constraint solving via fractional edge covers"
    - "greedy strategies and larger islands of tractability for conjunctive queries and constraint satisfaction problems"
    - "general and fractional hypertree decompositions hard and easy cases"
    - "aggregations over generalized hypertree decompositions"
    - "faq questions asked frequently"
    - "structural tractability of enumerating csp solutions"
    - "a quasi polynomial time partition oracle for graphs with an excluded minor"
    - "possibilistic constraint satisfaction problems or how to handle soft constraints"

Connected through hyperedge HE-4 (induced by source paper "the complexity of general valued csps seen from the other side"):
  with members:
    - "a dichotomy theorem for nonuniform csps"
    - "the proof of csp dichotomy conjecture"
    - "algebraic properties of valued constraint satisfaction problem"
    - "extended formulation for csp that is compact for instances of bounded treewidth"
    - "the complexity of general valued csps"
    - "a trichotomy in the complexity of counting answers to conjunctive queries"
    - "the power of linear programming for valued csps"
    - "tractable hypergraph properties for constraint satisfaction and conjunctive queries"

Connected through hyperedge HE-5 (induced by source paper "the complexity of finite valued csps"):
  with members:
    - "an algebraic theory of complexity for discrete optimization"
    - "the complexity of conservative valued csps"
    - "the power of linear programming for general valued csps"
    - "computational complexity of the minimum cost homomorphism problem on three element domains"
    - "tractable triangles and cross free convexity in discrete optimisation"
    - "the power of linear programming for valued csps"
    - "an effective fusion technique of cloud computing and networking series"
    - "the power of linear programming for valued csps a constructive characterization"

Connected through hyperedge HE-6 (induced by source paper "towards a characterization of constant factor approximable finite valued csps"):
  with members:
    - "a dichotomy theorem for nonuniform csps"
    - "the proof of csp dichotomy conjecture"
    - "the complexity of finite valued csps"
    - "asking the metaquestions in constraint tractability"
    - "robust algorithms with polynomial loss for near unanimity csps"
    - "combinatorial optimization algorithms via polymorphisms"
    - "the complexity of general valued csps"
    - "local distribution and the symmetry gap approximability of multiway partitioning problems"

Connected through hyperedge HE-7 (induced by source paper "structural decompositions for problems with global constraints"):
  with members:
    - "size bounds and query plans for relational joins"
    - "constraint solving via fractional edge covers"
    - "tractable combinations of global constraints"
    - "backdoors to satisfaction"
    - "decomposition of the nvalue constraint"
    - "the complexity of reasoning with global constraints"
    - "tractable hypergraph properties for constraint satisfaction and conjunctive queries"
    - "hypertree decompositions and tractable queries"

Connected through hyperedge HE-8 (induced by source paper "the complexity of general valued csps"):
  with members:
    - "the power of sherali adams relaxations for general valued csps"
    - "combinatorial optimization algorithms via polymorphisms"
    - "a galois connection for valued constraint languages of infinite size"
    - "algebraic properties of valued constraint satisfaction problem"
    - "effectiveness of structural restrictions for hybrid csps"
    - "local distribution and the symmetry gap approximability of multiway partitioning problems"
    - "sherali adams relaxations for valued csps"
    - "robustly solvable constraint satisfaction problems"

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.AI(Artificial Intelligence)