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: "model checking of ordered multi pushdown automata"
  Abstract: We address the verification problem of ordered multi-pushdown automata: A multi-stack extension of pushdown automata that comes with a constraint on stack transitions such that a pop can only be pe ...

Connected through hyperedge HE-1 (induced by source paper "revisiting underapproximate reachability for multipushdown systems"):
  with members:
    - "timed systems through the lens of logic"
    - "towards an efficient tree automata based technique for timed systems"
    - "analyzing timed systems using tree automata"

Connected through hyperedge HE-2 (induced by source paper "analyzing timed systems using tree automata"):
  with members:
    - "timed pushdown automata revisited"
    - "reachability problem for weak multi pushdown automata"

Connected through hyperedge HE-3 (induced by source paper "reachability analysis of first order definable pushdown systems"):
  with members:
    - "timed pushdown automata revisited"
    - "automata theory in nominal sets"
    - "saturation algorithms for model checking pushdown systems"
    - "reachability problem for weak multi pushdown automata"
    - "ltl with the freeze quantifier and register automata"
    - "alternating timed automata"

Connected through hyperedge HE-4 (induced by source paper "ordered tree pushdown systems"):
  with members:
    - "saturation algorithms for model checking pushdown systems"
    - "saturation of concurrent collapsible pushdown systems"
    - "strictness of the collapsible pushdown hierarchy"
    - "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 "saturation algorithms for model checking pushdown systems"):
  with members:
    - "saturation of concurrent collapsible pushdown systems"
    - "modeling and verification of infinite systems with resources"
    - "symbolic backwards reachability analysis for higher order pushdown systems"
    - "symbolic reachability analysis of higher order context free processes"

Connected through hyperedge HE-6 (induced by source paper "on the path width of integer linear programming"):
  with members:
    - "reachability analysis of communicating pushdown systems"
    - "a bi directional refinement algorithm for the calculus of co inductive constructions"
    - "a perfect model for bounded verification"

Connected through hyperedge HE-7 (induced by source paper "unified analysis of collapsible and ordered pushdown automata via term rewriting"):
  with members:
    - "symbolic reachability analysis of higher order context free processes"

Connected through hyperedge HE-8 (induced by source paper "saturation of concurrent collapsible pushdown systems"):
  with members:
    - "reachability analysis of communicating pushdown systems"

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)