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: "leftmost outermost beta reduction is invariant indeed"
  Abstract: Slot and van Emde Boas' weak invariance thesis states that reasonable machines can simulate each other within a polynomial overhead in time. Is λ-calculus a reasonable machine? Is there a way to measure the computational complexity of a λ-term? This paper presents the first complete positive answer to this long-standing problem. Moreover , our answer is completely machine-independent and based on a standard notion in the theory of λ-calculus: the length of a leftmost-outermost derivation to normal form is an invariant , i.e. reasonable, cost model. Such a theorem cannot be proved by directly relating λ-calculus with Turing machines or random access machines, because of the size-explosion problem: there are terms that in a linear number of steps produce an exponentially large output. The first step towards the solution is to shift to a notion of evaluation for which the length and the size of the output are linearly related. This is done by adopting the linear substitution calculus (LSC), a calculus of explicit substitutions modeled after linear logic proof nets and admitting a decomposition of leftmost-outermost derivations with the desired property. Thus, the LSC is invariant with respect to, say, random access machines. The second step is to show that the LSC is invariant with respect to the λ-calculus. The size explosion problem seems to imply that this is not possible: having the same notions of normal form, evaluation in the LSC is exponentially longer than in the λ-calculus. We solve such an impasse by introducing a new form of shared normal form and shared reduction , called useful. Useful evaluation produces a compact, shared representation of the normal form, by avoiding those steps that only unshare the output without contributing to β-redexes, i.e. the steps that cause the blow-up in size. The main technical contribution of the paper is indeed the definition of useful reductions and the thorough analysis of their properties.

Connected through hyperedge HE-1 (induced by source paper "the abstract machinery of interaction long version"):
  with members:
    - "crumbling abstract machines"
    - "proof nets and the linear substitution calculus"
    - "the geometry of parallelism classical probabilistic and quantum effects"
    - "on the relative usefulness of fireballs"
    - "abstract machines for dialogue games"

Connected through hyperedge HE-2 (induced by source paper "crumbling abstract machines"):
  with members:
    - "towards a semantic measure of the execution time in call by value lambda calculus"
    - "standardization and conservativity of a refined call by value lambda calculus"
    - "a strong distillery"
    - "on the relative usefulness of fireballs"

Connected through hyperedge HE-3 (induced by source paper "factorization and normalization essentially"):
  with members:
    - "standardization and conservativity of a refined call by value lambda calculus"
    - "on abstract normalisation beyond neededness"
    - "a standardisation proof for algebraic pattern calculi"

Connected through hyperedge HE-4 (induced by source paper "two formal systems of the lambda delta family revised"):
  with members:
    - "an extended type system with lambda typed lambda expressions"
    - "tight typings and split bounds"

Connected through hyperedge HE-5 (induced by source paper "combinatorics of explicit substitutions"):
  with members:
    - "counting environments and closures"
    - "normal order reduction grammars"
    - "combinatorics of lambda terms a natural approach"
    - "a natural counting of lambda terms"
    - "counting and generating terms in the binary lambda calculus extended version"
    - "modular complexity analysis for term rewriting"
    - "counting and generating lambda terms"
    - "on constructor rewrite systems and the lambda calculus"

Connected through hyperedge HE-6 (induced by source paper "on the enumeration of closures and environments with an application to random generation"):
  with members:
    - "combinatorics of explicit substitutions"
    - "normal order reduction grammars"
    - "a natural counting of lambda terms"
    - "counting and generating terms in the binary lambda calculus extended version"
    - "on constructor rewrite systems and the lambda calculus"
    - "smoothed analysis of algorithms why the simplex algorithm usually takes polynomial time"

Connected through hyperedge HE-7 (induced by source paper "tight typings and split bounds"):
  with members:
    - "call by need neededness and all that"
    - "the relational model is injective for multiplicative exponential linear logic"
    - "call by value non determinism in a linear logic type discipline"
    - "non idempotent intersection types and strong normalisation"
    - "a semantic account of strong normalization in linear logic"
    - "execution time of lambda terms via denotational semantics and intersection types"

Connected through hyperedge HE-8 (induced by source paper "the dynamic geometry of interaction machine a token guided graph rewriter"):
  with members:
    - "efficient implementation of evaluation strategies via token guided graph rewriting"
    - "the dynamic geometry of interaction machine a call by need graph rewriter"
    - "the complexity of abstract machines"
    - "the geometry of parallelism classical probabilistic and quantum effects"
    - "linear dependent types and relative completeness"

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)