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: "soft contract verification for higher order stateful programs"
  Abstract: Software contracts allow programmers to state rich program properties using the full expressive power of an object language. However, since they are enforced at runtime, monitoring contracts imposes significant overhead and delays error discovery. So contract veri cation aims to guarantee all or most of these properties ahead of time, enabling valuable optimizations and yielding a more general assurance of correctness. Existing methods for static contract verification satisfy the needs of more restricted target languages, but fail to address the challenges unique to those conjoining untyped, dynamic programming, higher-order functions, modularity, and statefulness. Our approach tackles all these features at once, in the context of the full Racket system—a mature environment for stateful, higher-order, multi-paradigm programming with or with- out types. Evaluating our method using a set of both pure and stateful benchmarks, we are able to verify 99.94% of checks statically (all but 28 of 49, 861).     Stateful, higher-order functions pose significant challenges for static contract verification in particular. In the presence of these features, a modular analysis must permit code from the current module to escape permanently to an opaque context (unspecified code from outside the current module) that may be stateful and therefore store a reference to the escaped closure. Also, contracts themselves, being predicates wri en in unrestricted Racket, may exhibit stateful behavior; a sound approach must be robust to contracts which are arbitrarily expressive and interwoven with the code they monitor. In this paper, we present and evaluate our solution based on higher-order symbolic execution, explain the techniques we used to address such thorny issues, formalize a notion of behavioral approximation, and use it to provide a mechanized proof of soundness.

Connected through hyperedge HE-1 (induced by source paper "size change termination as a contract"):
  with members:
    - "abstracting definitional interpreters functional pearl"
    - "soft contract verification"
    - "from safety to termination and back smt based verification for lazy languages"
    - "abstracting abstract machines a systematic approach to higher order program analysis"
    - "higher order symbolic execution via contracts"
    - "abstracting abstract machines"
    - "a dynamic approach to characterizing termination of general logic programs"

Connected through hyperedge HE-2 (induced by source paper "gradual liquid type inference"):
  with members:
    - "learning to blame localizing novice type errors with data driven diagnosis"
    - "refinement reflection complete verification with smt"
    - "dynamic witnesses for static type errors or ill typed programs usually go wrong"
    - "soft contract verification"
    - "higher order symbolic execution via contracts"

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)