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: "beyond language equivalence on visibly pushdown automata"
  Abstract: We study (bi)simulation-like preorder/equivalence checking on#N#the class of visibly pushdown automata and its natural#N#subclasses visibly BPA (Basic Process Algebra) and visibly#N#one-counter automata. We describe generic methods for proving#N#complexity upper and lower bounds for a number of studied#N#preorders and equivalences like simulation, completed#N#simulation, ready simulation, 2-nested simulation#N#preorders/equivalences and bisimulation equivalence. Our main#N#results are that all the mentioned equivalences and preorders#N#are EXPTIME-complete on visibly pushdown automata,#N#PSPACE-complete on visibly one-counter automata and P-complete#N#on visibly BPA. Our PSPACE lower bound for visibly one-counter#N#automata improves also the previously known DP-hardness results#N#for ordinary one-counter automata and one-counter nets.#N#Finally, we study regularity checking problems for visibly#N#pushdown automata and show that they can be decided in#N#polynomial time.

Connected through hyperedge HE-1 (induced by source paper "bisimulation equivalence of first order grammars is ackermann complete"):
  with members:
    - "equivalence of pushdown automata via first order grammars"
    - "complexity hierarchies beyond elementary"
    - "branching bisimilarity checking for prs"
    - "bisimulation equivalence of first order grammars"
    - "complexity bounds for ordinal based termination"
    - "bpa bisimilarity is exptime hard"
    - "the bisimulation problem for equational graphs of finite out degree"

Connected through hyperedge HE-2 (induced by source paper "expspace hardness of behavioural equivalences of succinct one counter nets"):
  with members:
    - "simulation problems over one counter nets"
    - "reachability in succinct one counter games"
    - "bpa bisimilarity is exptime hard"
    - "model checking probabilistic timed automata with one or two clocks"

Connected through hyperedge HE-3 (induced by source paper "minimization of visibly pushdown automata using partial max sat"):
  with members:
    - "reduction of nondeterministic tree automata"
    - "advanced automata minimization"
    - "b uchi automata can have smaller quotients"

Connected through hyperedge HE-4 (induced by source paper "simulation problems over one counter nets"):
  with members:
    - "infinite state energy games"
    - "decidability of weak simulation on one counter nets"
    - "simulation over one counter nets is pspace complete"
    - "equivalence checking on infinite state systems techniques and results"

Connected through hyperedge HE-5 (induced by source paper "bisimilarity on basic process algebra is in 2 exptime an explicit proof"):
  with members:
    - "bisimilarity of pushdown systems is nonelementary"
    - "bpa bisimilarity is exptime hard"
    - "the bisimulation problem for equational graphs of finite out degree"

Connected through hyperedge HE-6 (induced by source paper "simulation over one counter nets is pspace complete"):
  with members:
    - "decidability of weak simulation on one counter nets"
    - "equivalence checking on infinite state systems techniques and results"

Connected through hyperedge HE-7 (induced by source paper "decidability of weak simulation on one counter nets"):
  with members:
    - "branching time model checking of one counter processes"

Connected through hyperedge HE-8 (induced by source paper "bpa bisimilarity is exptime hard"):
  with members:
    - "bisimilarity on basic process algebra is in 2 exptime an explicit proof"
    - "decidability of higher order matching"
    - "model checking probabilistic timed automata with one or two clocks"
    - "equivalence checking on infinite state systems techniques and results"
    - "the bisimulation problem for equational graphs of finite out degree"

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.CC(Computational Complexity)