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: "refinement and difference for probabilistic automata"
  Abstract: This paper studies a difference operator for stochastic systems whose specifications are represented by Abstract Probabilistic Automata (APAs). In the case refinement fails between two specifications, the target of this operator is to produce a specification APA that represents all witness PAs of this failure. Our contribution is an algorithm that allows to approximate the difference of two APAs with arbitrary precision. Our technique relies on new quantitative notions of distances between APAs used to assess convergence of the approximations, as well as on an in-depth inspection of the refinement relation for APAs. The procedure is effective and not more complex to implement than refinement checking.

Connected through hyperedge HE-1 (induced by source paper "on the state complexity of closures and interiors of regular languages with subwords and superwords"):
  with members:
    - "decidability in the logic of subsequences and supersequences"
    - "finite automata for the sub and superword closure of cfls descriptional and computational complexity"
    - "alternating towers and piecewise testable separators"
    - "the power of priority channel systems"
    - "computing downward closures for stacked counter automata"
    - "quotient complexity of ideal languages"
    - "decision problems for convex languages"
    - "the computational complexity of universality problems for prefixes suffixes factors and subwords of regular languages"

Connected through hyperedge HE-2 (induced by source paper "compositionality for quantitative specifications"):
  with members:
    - "structural refinement for the modal nu calculus"
    - "hennessy milner logic with greatest fixed points as a complete behavioural specification theory"
    - "probabilistic modal mu calculus with independent product"
    - "a robust specification theory for modal event clock automata"
    - "weighted modal transition systems"
    - "a parametric counterexample refinement approach for robust timed specifications"

Connected through hyperedge HE-3 (induced by source paper "a survey on the local divisor technique"):
  with members:
    - "linear temporal logic for regular cost functions"
    - "regular languages are church rosser congruential"
    - "star free languages are church rosser congruential"

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)