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: "dividing line between decidable pda s and undecidable ones"
  Abstract: Senizergues has proved that language equivalence is decidable for disjoint epsilon-deterministic PDA. Stirling has showed that strong bisimilarity is decidable for PDA. On the negative side Srba demonstrated that the weak bisimilarity is undecidable for normed PDA. Later Jancar and Srba established the undecidability of the weak bisimilarity for disjoint epsilon-pushing PDA and disjoint epsilon-popping PDA. These decidability and undecidability results are extended in the present paper. The extension is accomplished by looking at the equivalence checking issue for the branching bisimilarity of several variants of PDA.

Connected through hyperedge HE-1 (induced by source paper "branching bisimilarity on normed bpa is exptime complete"):
  with members:
    - "a polynomial time algorithm for deciding branching bisimilarity on totally normed bpa"
    - "branching bisimilarity of normed bpa processes is in nexptime"
    - "branching bisimilarity checking for prs"
    - "bisimilarity on basic process algebra is in 2 exptime an explicit proof"
    - "bpa bisimilarity is exptime hard"
    - "equivalence checking on infinite state systems techniques and results"

Connected through hyperedge HE-2 (induced by source paper "bisimulation equivalence of first order grammars"):
  with members:
    - "complexity hierarchies beyond elementary"
    - "branching bisimilarity checking for prs"
    - "bisimilarity on basic process algebra is in 2 exptime an explicit proof"
    - "bpa bisimilarity is exptime hard"
    - "on the complexity of the equivalence problem for probabilistic automata"
    - "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.LO(Logic in Computer Science)