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: "the power of well structured systems"
  Abstract: Well-structured systems, aka WSTS, are computational models where the set of possible configurations is equipped with a well-quasi-ordering which is compatible with the transition relation between configurations. This structure supports generic decidability results that are important in verification and several other fields.#R##N##R##N#This paper recalls the basic theory underlying well-structured systems and shows how two classic decision algorithms can be formulated as an exhaustive search for some "bad" sequences. This lets us describe new powerful techniques for the complexity analysis of WSTS algorithms. Recently, these techniques have been successful in precisely characterizing the power, in a complexity-theoretical sense, of several important WSTS models like unreliable channel systems, monotonic counter machines, or networks of timed systems.

Connected through hyperedge HE-1 (induced by source paper "the ideal approach to computing closed subsets in well quasi orderings"):
  with members:
    - "mixed powerdomains for probability and nondeterminism"
    - "well behaved transition systems"
    - "complexity hierarchies beyond elementary"
    - "demystifying reachability in vector addition systems"
    - "finite automata for the sub and superword closure of cfls descriptional and computational complexity"
    - "the power of priority channel systems"
    - "complexity bounds for ordinal based termination"
    - "computing downward closures for stacked counter automata"

Connected through hyperedge HE-2 (induced by source paper "expressive power of broadcast consensus protocols"):
  with members:
    - "affine extensions of integer vector addition systems with states"
    - "controlling a population"
    - "space optimal majority in population protocols"
    - "time space trade offs in population protocols"
    - "context free commutative grammars with integer counters and resets"
    - "the computational power of population protocols"

Connected through hyperedge HE-3 (induced by source paper "complexity hierarchies beyond elementary"):
  with members:
    - "relating timed and register automata"
    - "demystifying reachability in vector addition systems"
    - "nonelementary complexities for branching vass mell and extensions"
    - "on freeze ltl with ordered attributes"
    - "trace inclusion for one counter nets revisited"
    - "the power of priority channel systems"
    - "the parametric ordinal recursive complexity of post embedding problems"
    - "graph logics with rational relations"

Connected through hyperedge HE-4 (induced by source paper "well behaved transition systems"):
  with members:
    - "reachability in two dimensional vector addition systems with states is pspace complete"
    - "context free commutative grammars with integer counters and resets"
    - "fixed dimensional energy games are in pseudo polynomial time"
    - "integer vector addition systems with states"
    - "kleene algebras and semimodules for energy problems"
    - "forward analysis for wsts part ii complete wsts"
    - "multiply recursive upper bounds with higman s lemma"
    - "forward analysis for wsts part i completions"

Connected through hyperedge HE-5 (induced by source paper "linear combinations of unordered data vectors"):
  with members:
    - "model checking flat freeze ltl on one counter automata"
    - "approaching the coverability problem continuously"
    - "homogeneous equations of algebraic petri nets"
    - "demystifying reachability in vector addition systems"
    - "automata theory in nominal sets"
    - "integer vector addition systems with states"

Connected through hyperedge HE-6 (induced by source paper "on reachability for unidirectional channel systems extended with regular tests"):
  with members:
    - "complexity hierarchies beyond elementary"
    - "generalized post embedding problems"
    - "the parametric ordinal recursive complexity of post embedding problems"
    - "graph logics with rational relations"
    - "reachability analysis of communicating pushdown systems"
    - "cutting through regular post embedding problems"
    - "reachability of communicating timed processes"
    - "multiply recursive upper bounds with higman s lemma"

Connected through hyperedge HE-7 (induced by source paper "a note on decidable separability by piecewise testable languages"):
  with members:
    - "on the state complexity of closures and interiors of regular languages with subwords and superwords"
    - "demystifying reachability in vector addition systems"
    - "an approach to computing downward closures"
    - "computing downward closures for stacked counter automata"
    - "the separation problem for regular languages by piecewise testable languages"
    - "separating regular languages by piecewise testable and unambiguous languages"
    - "piecewise testable tree languages"
    - "model checking vector addition systems with one zero test"

Connected through hyperedge HE-8 (induced by source paper "complexity bounds for ordinal based termination"):
  with members:
    - "complexity hierarchies beyond elementary"
    - "proving termination with transition invariants of height omega"
    - "ranking functions for linear constraint loops"
    - "bounded termination of monotonicity constraint transition systems"
    - "automated complexity analysis based on the dependency pair method"
    - "ackermannian and primitive recursive bounds with dickson s lemma"
    - "multiply recursive upper bounds with higman s lemma"

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)