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: "an improved envy free cake cutting protocol for four agents"
  Abstract: We consider the classic cake-cutting problem of producing envy-free allocations, restricted to the case of four agents. The problem asks for a partition of the cake to four agents, so that every agent finds her piece at least as valuable as every other agent's piece. The problem has had an interesting history so far. Although the case of three agents is solvable with less than 15 queries, for four agents no bounded procedure was known until the recent breakthroughs of Aziz and Mackenzie (STOC 2016, FOCS 2016). The main drawback of these new algorithms, however, is that they are quite complicated and with a very high query complexity. With four agents, the number of queries required is close to 600. In this work we provide an improved algorithm for four agents, which reduces the current complexity by a factor of 3.4. Our algorithm builds on the approach of Aziz and Mackenzie (STOC 2016) by incorporating new insights and simplifying several steps. Overall, this yields an easier to grasp procedure with lower complexity.

Connected through hyperedge HE-1 (induced by source paper "computing exact solutions of consensus halving and the borsuk ulam theorem"):
  with members:
    - "approximating the existential theory of the reals"
    - "the complexity of splitting necklaces and bisecting ham sandwiches"
    - "consensus halving is ppa complete"
    - "a discrete and bounded envy free cake cutting protocol for any number of agents"
    - "hardness results for consensus halving"
    - "recognition and complexity of point visibility graphs"
    - "a discrete and bounded envy free cake cutting protocol for four agents"
    - "inapproximability of nash equilibrium"

Connected through hyperedge HE-2 (induced by source paper "maximin aware allocations of indivisible goods"):
  with members:
    - "groupwise maximin fair allocation of indivisible goods"
    - "almost envy freeness with general valuations"
    - "networked fairness in cake cutting"
    - "fair division of a graph"
    - "fair division via social comparison"

Connected through hyperedge HE-3 (induced by source paper "cake cutting on graphs a discrete and bounded proportional protocol"):
  with members:
    - "networked fairness in cake cutting"
    - "a discrete and bounded envy free cake cutting protocol for any number of agents"
    - "fair division via social comparison"
    - "a discrete and bounded envy free cake cutting protocol for four agents"

Connected through hyperedge HE-4 (induced by source paper "fairly allocating many goods with few queries"):
  with members:
    - "fairly allocating contiguous blocks of indivisible items"
    - "approximation algorithms for computing maximin share allocations"
    - "almost envy freeness with general valuations"
    - "fair division of a 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.GT(Computer Science and Game Theory)