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: "friends ftw friendship and competition in halo reach"
  Abstract: How important are friendships in determining success by individuals and teams in complex collaborative environments? By combining a novel data set containing the dynamics of millions of ad hoc teams from the popular multiplayer online first person shooter Halo: Reach with survey data on player demographics, play style, psychometrics and friendships derived from an anonymous online survey, we investigate the impact of friendship on collaborative and competitive performance. In addition to finding significant differences in player behavior across these variables, we find that friendships exert a strong influence, leading to both improved individual and team performance - even after controlling for the overall expertise of the team - and increased pro-social behaviors. Players also structure their in-game activities around social opportunities, and as a result hidden friendship ties can be accurately inferred directly from behavioral time series. Virtual environments that enable such friendship effects will thus likely see improved collaboration and competition.

Connected through hyperedge HE-1 (induced by source paper "an empirical study on team formation in online games"):
  with members:
    - "the proficiency congruency dilemma virtual team design and performance in multiplayer online games"
    - "friends ftw friendship and competition in halo reach"
    - "smote synthetic minority over sampling technique"

Connected through hyperedge HE-2 (induced by source paper "the proficiency congruency dilemma virtual team design and performance in multiplayer online games"):
  with members:
    - "player behavior and optimal team composition for online multiplayer games"
    - "exploring cyberbullying and other toxic behavior in team competition online games"
    - "analyzing organizational routines in online knowledge collaborations a case for sequence analysis in cscw"
    - "stfu noob predicting crowdsourced decisions on toxic behavior in online games"
    - "friends ftw friendship and competition in halo reach"

Connected through hyperedge HE-3 (induced by source paper "exploring cyberbullying and other toxic behavior in team competition online games"):
  with members:
    - "linguistic analysis of toxic behavior in an online video game"
    - "stfu noob predicting crowdsourced decisions on toxic behavior in online games"
    - "friends ftw friendship and competition in halo reach"

Connected through hyperedge HE-4 (induced by source paper "social network dynamics in a massive online game network turnover non densification and team engagement in halo reach"):
  with members:
    - "social resilience in online communities the autopsy of friendster"
    - "detecting friendship within dynamic online interaction networks"
    - "friends ftw friendship and competition in halo reach"
    - "the anatomy of the facebook social graph"

Connected through hyperedge HE-5 (induced by source paper "detecting friendship within dynamic online interaction networks"):
  with members:
    - "nonparametric link prediction in dynamic networks"
    - "friends ftw friendship and competition in halo reach"
    - "the anatomy of the facebook social graph"

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)