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"
  Abstract: Behavioral software contracts are a widely used mechanism for governing the flow of values between components. However, run-time monitoring and enforcement of contracts imposes significant overhead and delays discovery of faulty components to run-time.   To overcome these issues, we present soft contract verification, which aims to statically prove either complete or partial contract correctness of components, written in an untyped, higher-order language with first-class contracts. Our approach uses higher-order symbolic execution, leveraging contracts as a source of symbolic values including unknown behavioral values, and employs an updatable heap of contract invariants to reason about flow-sensitive facts. We prove the symbolic execution soundly approximates the dynamic semantics and that verified programs can't be blamed.   The approach is able to analyze first-class contracts, recursive data structures, unknown functions, and control-flow-sensitive refinements of values, which are all idiomatic in dynamic languages. It makes effective use of an off-the-shelf solver to decide problems without heavy encodings. The approach is competitive with a wide range of existing tools - including type systems, flow analyzers, and model checkers - on their own benchmarks.

Connected through hyperedge HE-1 (induced by source paper "size change termination as a contract"):
  with members:
    - "soft contract verification for higher order stateful programs"
    - "abstracting definitional interpreters functional pearl"
    - "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"
    - "soft contract verification for higher order stateful programs"
    - "refinement reflection complete verification with smt"
    - "dynamic witnesses for static type errors or ill typed programs usually go wrong"
    - "higher order symbolic execution via contracts"

Connected through hyperedge HE-3 (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"
    - "pushdown flow analysis with abstract garbage collection"
    - "simulation of two way pushdown automata revisited"
    - "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-4 (induced by source paper "soft contract verification for higher order stateful programs"):
  with members:
    - "pushdown control flow analysis for free"
    - "dependent types for javascript"
    - "higher order symbolic execution via contracts"
    - "abstracting abstract machines"

Connected through hyperedge HE-5 (induced by source paper "combining static and dynamic contract checking for curry"):
  with members:
    - "default rules for curry"
    - "currycheck checking properties of curry programs"

Connected through hyperedge HE-6 (induced by source paper "trust but verify two phase typing for dynamic languages"):
  with members:
    - "elaborating intersection and union types"
    - "untangling typechecking of intersections and unions"

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)