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: "a finer reduction of constraint problems to digraphs"
  Abstract: It is well known that the constraint satisfaction problem over a general#N#relational structure A is polynomial time equivalent to the constraint problem#N#over some associated digraph. We present a variant of this construction and#N#show that the corresponding constraint satisfaction problem is logspace#N#equivalent to that over A. Moreover, we show that almost all of the commonly#N#encountered polymorphism properties are held equivalently on the A and the#N#constructed digraph. As a consequence, the Algebraic CSP dichotomy conjecture#N#as well as the conjectures characterizing CSPs solvable in logspace and in#N#nondeterministic logspace are equivalent to their restriction to digraphs.

Connected through hyperedge HE-1 (induced by source paper "binarisation for valued constraint satisfaction problems"):
  with members:
    - "the power of sherali adams relaxations for general valued csps"
    - "a galois connection for weighted relational clones of infinite size"
    - "algebraic properties of valued constraint satisfaction problem"
    - "a reduction from valued csp to min cost homomorphism problem for digraphs"
    - "the complexity of general valued csps"
    - "sherali adams relaxations for valued csps"
    - "robustly solvable constraint satisfaction problems"
    - "an algebraic theory of complexity for discrete optimization"

Connected through hyperedge HE-2 (induced by source paper "promise constraint satisfaction algebraic structure and a symmetric boolean dichotomy"):
  with members:
    - "dichotomy for digraph homomorphism problems two algorithms"
    - "combinatorial optimization algorithms via polymorphisms"
    - "the complexity of general valued csps"
    - "conservative constraint satisfaction re revisited"

Connected through hyperedge HE-3 (induced by source paper "refuting feder kinne and rafiey"):
  with members:
    - "a dichotomy theorem for nonuniform csps"
    - "the proof of csp dichotomy conjecture"
    - "constraint satisfaction problems over semilattice block mal tsev algebras"

Connected through hyperedge HE-4 (induced by source paper "a reduction from valued csp to min cost homomorphism problem for digraphs"):
  with members:
    - "algebraic properties of valued constraint satisfaction problem"
    - "the complexity of general valued csps"
    - "an algebraic theory of complexity for discrete optimization"
    - "on the reduction of the csp dichotomy conjecture to digraphs"
    - "computational complexity of the minimum cost homomorphism problem on three element domains"
    - "extensions of the minimum cost homomorphism problem"

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.CC(Computational Complexity)