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 games on higher order pushdown automata"
  Abstract: We prove an n-EXPTIME lower bound for the problem of deciding the winner in a reachability game on Higher Order Pushdown Automata (HPDA) of level n. This bound matches the known upper bound for parity games on HPDA. As a consequence the mu-calculus model checking over graphs given by n-HPDA is n-EXPTIME complete.

Connected through hyperedge HE-1 (induced by source paper "decision procedures for path feasibility of string manipulating programs with complex operations"):
  with members:
    - "what is decidable about string constraints with the replaceall function"
    - "graph logics with rational relations"
    - "recompression a simple and powerful technique for word equations"

Connected through hyperedge HE-2 (induced by source paper "parity to safety in polynomial time for pushdown and collapsible pushdown systems"):
  with members:
    - "proving liveness of parameterized programs"

Connected through hyperedge HE-3 (induced by source paper "annotated stack trees"):
  with members:
    - "saturation of concurrent collapsible pushdown systems"
    - "senescent ground tree rewrite systems"
    - "symbolic reachability analysis of higher order context free processes"

Connected through hyperedge HE-4 (induced by source paper "complexity of model checking recursion schemes for fragments of the modal mu calculus"):
  with members:
    - "the safe lambda calculus"
    - "a finite semantics of simply typed lambda terms for infinite runs of automata"

Connected through hyperedge HE-5 (induced by source paper "model checking branching time properties of multi pushdown systems is hard"):
  with members:
    - "reachability analysis of communicating pushdown systems"
    - "context bounded analysis for concurrent programs with dynamic creation of threads"

Connected through hyperedge HE-6 (induced by source paper "topological complexity of context free omega languages a survey"):
  with members:
    - "borel hierarchy and omega context free languages"
    - "on omega context free languages which are borel sets of infinite rank"
    - "an effective extension of the wagner hierarchy to blind counter automata"
    - "on winning conditions of high borel complexity in pushdown games"
    - "wadge degrees of infinitary rational relations"
    - "borel ranks and wadge degrees of context free omega languages"

Connected through hyperedge HE-7 (induced by source paper "symbolic backwards reachability analysis for higher order pushdown systems"):
  with members:
    - "symbolic reachability analysis of higher order context free processes"

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)