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: "concurrent timed port automata"
  Abstract: We present a new and powerful class of automata which are explicitly concurrent and allow a very simple definition of composition. The novelty of these automata is their time-synchronous message-asynchronous communication mechanism. Time synchrony is obtained by using global clock. Message asynchrony is obtained by requiring the automata to react to every input. Explicit concurrency is obtained by marking each transition with a set of input and output messages. We compare these automata with a history based approach which uses the same communication mechanism and show that they are equivalent.

Connected through hyperedge HE-1 (induced by source paper "architecture and behavior modeling of cyber physical systems with montiarcautomaton"):
  with members:
    - "towards a semantics of activity diagrams with semantic variation points"
    - "systems views and models of uml"
    - "system model semantics of class diagrams"
    - "modal object diagrams"
    - "cd2alloy class diagrams analysis using alloy revisited"
    - "montiarcautomaton modeling architecture and behavior of robotic systems"
    - "montiarc architectural modeling of interactive distributed and cyber physical systems"
    - "view based modeling of function nets"

Connected through hyperedge HE-2 (induced by source paper "systems views and models of uml"):
  with members:
    - "state based service description"
    - "enhancing the syslab system model with state"
    - "a stream based mathematical model for distributed information processing systems the syslab system model"
    - "towards a precise semantics for object oriented modeling techniques"

Connected through hyperedge HE-3 (induced by source paper "towards a system model for uml the structural data model"):
  with members:
    - "a stream based mathematical model for distributed information processing systems the syslab system model"

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.FL(Formal Languages and Automata Theory)