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: "mutable wadlerfest dot"
  Abstract: The Dependent Object Types (DOT) calculus aims to model the essence of Scala, with a focus on abstract type members, path-dependent types, and subtyping. Other Scala features could be defined by translation to DOT. Mutation is a fundamental feature of Scala currently missing in DOT. Mutation in DOT is needed not only to model effectful computation and mutation in Scala programs, but even to precisely specify how Scala initializes immutable variables and fields (vals). We present an extension to DOT that adds typed mutable reference cells. We have proven the extension sound with a mechanized proof in Coq. We present the key features of our extended calculus and its soundness proof, and discuss the challenges that we encountered in our search for a sound design and the alternative solutions that we considered.

Connected through hyperedge HE-1 (induced by source paper "towards algorithmic typing for d"):
  with members:
    - "a simple soundness proof for dependent object types"

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)