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: "on the flatness of immediate observation petri nets"
  Abstract: In a previous paper we introduced immediate observation (IO) Petri nets, a class of interest in the study of population protocols (a model of distributed computation), and enzymatic chemical networks. We showed that many problems for this class are PSPACE-complete, including parameterized problems asking whether an infinite set of Petri nets with the same underlying net but different initial markings satisfy a given property. The proofs of PSPACE inclusion did not provide explicit algorithms, leaving open the question of practical verification procedures. In the first part of this paper we show that IO Petri nets are globally flat, thus allowing their safety properties to be checked by efficient symbolic model checking tools using acceleration techniques, like FAST. #R##N#In the second part, we extend IO nets in two natural ways: by lifting the restriction on the number of so-called "observed" places, and by lifting the restriction on so-called "destination" places. The first extension proves to be essentially equivalent to the IO model. The second extension however is much more expressive and is no longer globally flat, but we show that its parametrized reachability, coverability and liveness problems remain decidable in PSPACE. Additionally, we observe that the pre-image computation for this second extension is locally flat, which allows application of tools like FAST to the reachability problem. This second class captures in a simple way the core reason that the IO models allow verification in PSPACE, and we believe it is of independent theoretical interest.

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)