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: "extending acl2 with smt solvers"
  Abstract: We present our extension of ACL2 with Satisfiability Modulo Theories (SMT) solvers using ACL2's trusted clause processor mechanism. We are particularly interested in the verification of physical systems including Analog and Mixed-Signal (AMS) designs. ACL2 offers strong induction abilities for reasoning about sequences and SMT complements deduction methods like ACL2 with fast nonlinear arithmetic solving procedures. While SAT solvers have been integrated into ACL2 in previous work, SMT methods raise new issues because of their support for a broader range of domains including real numbers and uninterpreted functions. This paper presents Smtlink, our clause processor for integrating SMT solvers into ACL2. We describe key design and implementation issues and describe our experience with its use.

Connected through hyperedge HE-1 (induced by source paper "a survey on theorem provers in formal methods"):
  with members:
    - "comparison of two theorem provers isabelle hol and coq"
    - "the boyer moore waterfall model revisited"
    - "reinforcement learning of theorem proving"
    - "qwire practice formal verification of quantum circuits in coq"
    - "proofwatch watchlist guidance for large theories in e"
    - "verifying asymptotic time complexity of imperative programs in isabelle"
    - "formalized lambek calculus in higher order logic hol4"
    - "the x86isa books features usage and future plans"

Connected through hyperedge HE-2 (induced by source paper "incremental sat library integration using abstract stobjs"):
  with members:
    - "verified aig algorithms in acl2"
    - "abstract stobjs and their application to isa modeling"
    - "bit blasting acl2 theorems"

Connected through hyperedge HE-3 (induced by source paper "computer assisted proving of combinatorial conjectures over finite domains a case study of a chess conjecture"):
  with members:
    - "ursa a system for uniform reduction to sat"
    - "learning assisted automated reasoning with flyspeck"
    - "integrating testing and interactive theorem proving"

Connected through hyperedge HE-4 (induced by source paper "real vector spaces and the cauchy schwarz inequality in acl2 r"):
  with members:
    - "convex functions in acl2 r"
    - "the cayley dickson construction in acl2"

Connected through hyperedge HE-5 (induced by source paper "smtlink 2 0"):
  with members:
    - "meta extract using existing facts in meta reasoning"
    - "refinement reflection complete verification with smt"

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.LO(Logic in Computer Science)