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: "a hiking trip through the orders of magnitude deriving efficient generators for closed simply typed lambda terms and normal forms"
  Abstract: Contrary to several other families of lambda terms, no closed formula or generating function is known and none of the sophisticated techniques devised in analytic combinatorics can currently help with counting or generating the set of {\em simply-typed closed lambda terms} of a given size. #R##N#Moreover, their asymptotic scarcity among the set of closed lambda terms makes counting them via brute force generation and type inference quickly intractable, with previous published work showing counts for them only up to size 10. #R##N#By taking advantage of the synergy between logic variables, unification with occurs check and efficient backtracking in today's Prolog systems, we climb 4 orders of magnitude above previously known counts by deriving progressively faster Horn Clause programs that generate and/or count the set of closed simply-typed lambda terms of sizes up to 14. A similar count for {\em closed simply-typed normal forms} is also derived up to size 14. #R##N#{\em {\bf Keywords:} logic programming transformations, type inference, combinatorics of lambda terms, simply-typed lambda calculus, simply-typed normal forms. }

Connected through hyperedge HE-1 (induced by source paper "formula transformers and combinatorial test generators for propositional intuitionistic theorem provers"):
  with members:
    - "modality definition synthesis for epistemic intuitionistic logic via a theorem prover"
    - "on uniquely closable and uniquely typable skeletons of lambda terms"
    - "random generation of closed simply typed lambda terms a synergy between logic programming and boltzmann samplers"
    - "a natural counting of lambda terms"
    - "counting and generating terms in the binary lambda calculus extended version"
    - "a logic programming playground for lambda terms combinators types and tree based arithmetic computations"
    - "counting and generating lambda terms"

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)