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: "the complexity of multiwinner voting rules with variable number of winners"
  Abstract: We consider the approval-based model of elections, and undertake a computational study of voting rules which select committees whose size is not predetermined. While voting rules that output committees with a predetermined number of winning candidates are quite well studied, the study of elections with variable number of winners has only recently been initiated by Kilgour. This paper aims at achieving a better understanding of these rules, their computational complexity, and on scenarios for which they might be applicable.

Connected through hyperedge HE-1 (induced by source paper "aggregation over metric spaces proposing and voting in elections budgeting and legislation"):
  with members:
    - "on computing centroids according to the p norms of hamming distance vectors"
    - "point foundations of e democracy"
    - "incorporating reality into social choice"
    - "proportionally representative participatory budgeting axioms and algorithms"
    - "sequential deliberation for social choice"
    - "metric distortion of social choice rules lower bounds and fairness properties"
    - "the core of the participatory budgeting problem"
    - "iterative judgment aggregation"

Connected through hyperedge HE-2 (induced by source paper "how hard is it to control a group"):
  with members:
    - "structure in dichotomous preferences"
    - "computational aspects of multi winner approval voting"
    - "the control complexity of r approval from the single peaked case to the general case"
    - "the complexity of manipulating k approval elections"
    - "anyone but him the complexity of precluding an alternative"

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.GT(Computer Science and Game Theory)