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: "efx exists for three agents"
  Abstract: We study the problem of allocating a set of indivisible items among agents with additive valuations in a fair manner. Envy-freeness up to any item (EFX) is arguably the most compelling fairness concept for this problem. However, despite significant efforts by many researchers for several years, its existence has not been settled beyond the simple case of two agents. In this paper, we break this barrier by showing that an EFX allocation always exists for three agents! Our proof is algorithmic and quite involved. Furthermore, we also falsify a conjecture of Caragiannis et al. by showing an instance with three agents for which there is a partial EFX allocation (some items are not allocated) with higher Nash welfare than that of any complete EFX allocation.

Connected through hyperedge HE-1 (induced by source paper "fair division of mixed divisible and indivisible goods"):
  with members:
    - "an improved approximation algorithm for maximin shares"
    - "monotonicity and competitive equilibrium in cake cutting"
    - "truthful fair division without free disposal"
    - "approximation algorithms for computing maximin share allocations"
    - "almost envy freeness with general valuations"
    - "the query complexity of cake cutting"
    - "a discrete and bounded envy free cake cutting protocol for any number of agents"
    - "a discrete and bounded envy free cake cutting protocol for four agents"

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)