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: "weighted reciprocity in human communication networks"
  Abstract: In this paper we define a metric for reciprocity appropriate for weighted networks in order to investigate the distribution of reciprocity in a large-scale social network composed of billions of communication attempts across millions of actors. We find that relations in this network are characterized by much larger degrees of non-reciprocity than we would expect if persons kept only those relationships that exhibit balance. We point to two structural features of human communication behavior and relationship formation—the division of contacts into strong and weak ties and the tendency to form relationships with similar others—that either help or hinder the ability of persons to obtain balance in their relationships. We examine the extent to which deviations from reciprocity in the observed network are partially traceable to these characteristics.

Connected through hyperedge HE-1 (induced by source paper "dynamics of trust reciprocation in heterogenous mmog networks"):
  with members:
    - "a scalable null model for directed graphs matching all degree distributions in out and reciprocal"
    - "twitter reciprocal reply networks exhibit assortativity with respect to happiness"

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.SI(Social and Information Networks)