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: "simulation of two way pushdown automata revisited"
  Abstract: The linear-time simulation of 2-way deterministic pushdown automata (2DPDA) by the Cook and Jones constructions is revisited. Following the semantics-based approach by Jones, an interpreter is given which, when extended with random-access memory, performs a linear-time simulation of 2DPDA. The recursive interpreter works without the dump list of the original constructions, which makes Cook's insight into linear-time simulation of exponential-time automata more intuitive and the complexity argument clearer. The simulation is then extended to 2-way nondeterministic pushdown automata (2NPDA) to provide for a cubic-time recognition of context-free languages. The time required to run the final construction depends on the degree of nondeterminism. The key mechanism that enables the polynomial-time simulations is the sharing of computations by memoization.

Connected through hyperedge HE-1 (induced by source paper "abstracting definitional interpreters functional pearl"):
  with members:
    - "pushdown control flow analysis for free"
    - "galois transformers and modular abstract interpreters reusable metatheory for program analysis"
    - "soft contract verification"
    - "pushdown flow analysis with abstract garbage collection"
    - "abstracting abstract control extended"
    - "introspective pushdown analysis of higher order programs"
    - "systematic abstraction of abstract machines"
    - "cfa2 a context free approach to control flow analysis"

Connected through hyperedge HE-2 (induced by source paper "memoization for unary logic programming characterizing ptime"):
  with members:
    - "characterizing co nl by a group action"
    - "interaction graphs graphings"
    - "unification and logarithmic space"
    - "logic programming and logarithmic space"
    - "an implicit characterization of pspace"
    - "light types for polynomial time computation in lambda calculus"

Connected through hyperedge HE-3 (induced by source paper "abstracting abstract control extended"):
  with members:
    - "optimizing abstract abstract machines"
    - "introspective pushdown analysis of higher order programs"
    - "systematic abstraction of abstract machines"
    - "cfa2 a context free approach to control flow analysis"
    - "pushdown control flow analysis of higher order programs"
    - "abstracting abstract machines"
    - "first order and temporal logics for nested words"

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.PL(Programming Languages)