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: "np completeness of the negative k cycle problem"
  Abstract: Given a positive integer $k$ and a directed graph with real edge cost, the negative $k$-cycle problem ($k$NCP) is to determine whether there exists a negative cycle with at least $k$ edges. The $k$NCP problem generalizes two well known problems: The negative cycle detection problem of determining whether there exist negative cycles in a given graph, and the $k$-cycle problem of determining whether there exist a cycle with at least $k$ edges. #R##N#This paper proves the ${\cal NP}$-completeness of $k$NCP for any fixed $k\geq3$ by giving a reduction from the 3 occurrence 3-Satisfiability (\emph{3O3SAT}) problem. Compared to the fact that the negative cycle detection problem is polynomial solvable and the $k$-cycle problem is fixed-parameter tractable with respect to $k$, the hardness result for $k$NCP seems interesting.

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)