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: "monotonic references for gradual typing"
  Abstract: Gradual typing enables both static and dynamic typing in the same program, and makes it convenient to migrate code between the two typing disciplines. We have had a satisfactory static semantics for gradual typing for some time but the dynamic semantics has proved much more difficult, raising numerous research challenges. Ongoing efforts to integrate gradual typing into existing functional and object-oriented languages revealed problems regarding space efficiency, run-time overhead, and object identity. While the first problem has been solved, the later two problems remain open. The essence of these problems is best studied in the context of the gradually-typed lambda calculus with mutable references. In this paper we present a new dynamic semantics called monotonic references, which does not require proxies, thereby solving the object identity problem, and is the first to completely eliminate run-time overhead in statically typed code while maintaining the flexibility of gradual typing. With our design, casting a reference may cause a heap cell to become less dynamically typed (but not more). However, retaining type safety is challenging in a semantics such as this that allows strong updates to the heap. Nevertheless, we present a mechanized proof that monotonic references are type safe. We also present a blame tracking strategy for monotonic references and prove the blame theorem.

Connected through hyperedge HE-1 (induced by source paper "toward a mechanized compendium of gradual typing"):
  with members:
    - "gradual typing in an open world"

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)