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: "abstract stobjs and their application to isa modeling"
  Abstract: We introduce a new ACL2 feature, the abstract stobj, and show how to apply it to modeling the instruction set architecture of a microprocessor. Benefits of abstract stobjs over traditional ("concrete") stobjs can include faster execution, support for symbolic simulation, more efficient reasoning, and resilience of proof developments under modeling optimization.

Connected through hyperedge HE-1 (induced by source paper "a formalisation of the sparc tso memory model for multi core machine code"):
  with members:
    - "fast and generalized polynomial time memory consistency verification"

Connected through hyperedge HE-2 (induced by source paper "incremental sat library integration using abstract stobjs"):
  with members:
    - "extending acl2 with smt solvers"
    - "verified aig algorithms in acl2"
    - "bit blasting acl2 theorems"

Connected through hyperedge HE-3 (induced by source paper "adding 32 bit mode to the acl2 model of the x86 isa"):
  with members:
    - "the x86isa books features usage and future plans"
    - "a versatile sound tool for simplifying definitions"
    - "bit blasting acl2 theorems"

Connected through hyperedge HE-4 (induced by source paper "formalising filesystems in the acl2 theorem prover an application to fat32"):
  with members:
    - "fix your types"

Connected through hyperedge HE-5 (induced by source paper "the x86isa books features usage and future plans"):
  with members:
    - "bit blasting acl2 theorems"

Connected through hyperedge HE-6 (induced by source paper "fix your types"):
  with members:
    - "polymorphic types in acl2"
    - "development of a translator from llvm to acl2"
    - "data definitions in the acl2 sedan"
    - "a formalisation of xmas"
    - "bit blasting acl2 theorems"

Connected through hyperedge HE-7 (induced by source paper "enhancements to acl2 in versions 5 0 6 0 and 6 1"):
  with members:
    - "how can i do that with acl2 recent enhancements to acl2"

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)