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: "proceedings 10th international workshop on the acl2 theorem prover and its applications"
  Abstract: This volume contains the proceedings of ACL2 2011, the International Workshop on the ACL2 Theorem Prover and its Applications. The workshop was held in Austin, Texas, USA, on November 3-4 2011. ACL2 2011 is the tenth in a series of workshops on the ACL2 Theorem Prover and its Applications. The workshop was co-located with the eleventh Conference on Formal Methods in Computer Aided Design (FMCAD'11). The ACL2 Workshop series provide a major technical forum for researchers to present and discuss improvements and extensions to the theorem prover, comparisons of ACL2 with other systems, and applications of ACL2 in formal verification or formalized mathematics. Workshops have been held at approxiamately 18 month intervals since 1999. ACL2 is the most recent incarnation of the Boyer-Moore family of theorem provers, for which, Robert Boyer, Matt Kaufmann and J Strother Moore received the 2005 ACM Software System Award. It is state-of-the-art automated reasoning system that has been successfully used in academia, government and industry for specification and verification of computing systems. More details can be found in the proceedings and on the workshop web page (www.cs.ru.nl/~julien/acl2-11/).

Connected through hyperedge HE-1 (induced by source paper "proceedings of the 15th international workshop on the acl2 theorem prover and its applications a toolbox for property checking from simulation using incremental sat extended abstract"):
  with members:
    - "proceedings twelfth international workshop on the acl2 theorem prover and its applications"
    - "proceedings international workshop on the acl2 theorem prover and its applications"
    - "verified aig algorithms in acl2"
    - "bit blasting acl2 theorems"

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)