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: "relaxed operational semantics of concurrent programming languages"
  Abstract: We propose a novel, operational framework to formally describe the semantics of concurrent programs running within the context of a relaxed memory model. Our framework features a "temporary store" where the memory operations issued by the threads are recorded, in program order. A memory model then specifies the conditions under which a pending operation from this sequence is allowed to be globally performed, possibly out of order. The memory model also involves a "write grain," accounting for architectures where a thread may read a write that is not yet globally visible. Our formal model is supported by a software simulator, allowing us to run litmus tests in our semantics.

Connected through hyperedge HE-1 (induced by source paper "generating representative executions extended abstract"):
  with members:
    - "stateless model checking for tso and pso"

Connected through hyperedge HE-2 (induced by source paper "stateless model checking for power"):
  with members:
    - "stateless model checking for tso and pso"
    - "robustness against power is pspace complete"
    - "herding cats modelling simulation testing and data mining for weak memory"
    - "software verification for weak memory via program transformation"

Connected through hyperedge HE-3 (induced by source paper "operational aspects of c c concurrency"):
  with members:
    - "on thin air reads towards an event structures model of relaxed memory"
    - "new lace and arsenic adventures in weak memory with a program logic"
    - "specifying and verifying concurrent algorithms with histories and subjectivity"

Connected through hyperedge HE-4 (induced by source paper "herding cats modelling simulation testing and data mining for weak memory"):
  with members:
    - "software verification for weak memory via program transformation"
    - "checking robustness against tso"
    - "a unified theory of shared memory consistency"

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.PL(Programming Languages)