human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "combinatorics of explicit substitutions"):
  Abstract: $\lambda\upsilon$ is an extension of the $\lambda$-calculus which internalises the calculus of substitutions. In the current paper, we investigate the combinatorial properties of $\lambda\upsilon$ focusing on the quantitative aspects of substitution resolution. We exhibit an unexpected correspondence between the counting sequence for $\lambda\upsilon$-terms and famous Catalan numbers. As a by-product, we establish effective sampling schemes for random $\lambda\upsilon$-terms. We show that typical $\lambda\upsilon$-terms represent, in a strong sense, non-strict computations in the classic $\lambda$-calculus. Moreover, typically almost all substitutions are in fact suspended, i.e. unevaluated, under closures. Consequently, we argue that $\lambda\upsilon$ is an intrinsically non-strict calculus of explicit substitutions. Finally, we investigate the distribution of various redexes governing the substitution resolution in $\lambda\upsilon$ and investigate the quantitative contribution of various substitution primitives.

Includes members:
  Member "counting environments and closures":
    also connected through other hyperedges:
      (none)
  Member "normal order reduction grammars":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "on the enumeration of closures and environments with an application to random generation")
  Member "combinatorics of lambda terms a natural approach":
    also connected through other hyperedges:
      (none)
  Member "leftmost outermost beta reduction is invariant indeed":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "the abstract machinery of interaction long version")
  Member "a natural counting of lambda terms":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "formula transformers and combinatorial test generators for propositional intuitionistic theorem provers")
  Member "counting and generating terms in the binary lambda calculus extended version":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "position paper towards transparent machine learning")
  Member "modular complexity analysis for term rewriting":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "analysing the complexity of functional programs higher order meets first order long version")
  Member "counting and generating lambda terms":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "formula transformers and combinatorial test generators for propositional intuitionistic theorem provers")

Question: Please tell me which class the source paper 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.LO(Logic in Computer Science)