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: "fedora an architecture for complex objects and their relationships"
  Abstract: The Fedora architecture is an extensible framework for the storage, management, and dissemination of complex objects and the relationships among them. Fedora accommodates the aggregation of local and distributed content into digital objects and the association of services with objects. This al-lows an object to have several accessible representations, some of them dy-namically produced. The architecture includes a generic RDF-based relation-ship model that represents relationships among objects and their components. Queries against these relationships are supported by an RDF triple store. The architecture is implemented as a web service, with all aspects of the complex object architecture and related management functions exposed through REST and SOAP interfaces. The implementation is available as open-source soft-ware, providing the foundation for a variety of end-user applications for digital libraries, archives, institutional repositories, and learning object systems.

Connected through hyperedge HE-1 (induced by source paper "web synchronization simulations using the resourcesync framework"):
  with members:
    - "resourcesync leveraging sitemaps for resource synchronization"
    - "memento time travel for the web"

Connected through hyperedge HE-2 (induced by source paper "adding escience assets to the data web"):
  with members:
    - "object re use exchange a resource centric approach"

Connected through hyperedge HE-3 (induced by source paper "the adore federation architecture"):
  with members:
    - "pathways augmenting interoperability across scholarly repositories"
    - "adore a modular standards based digital object repository"
    - "representing digital assets using mpeg 21 digital item declaration"
    - "file based storage of digital objects and constituent datastreams xmltapes and internet archive arc files"

Connected through hyperedge HE-4 (induced by source paper "ncore architecture and implementation of a flexible collaborative digital library"):
  with members:
    - "representing contextualized information in the nsdl"
    - "metadata aggregation and automated digital libraries a retrospective on the nsdl experience"
    - "adapting cbpp platforms for instructional use"
    - "an information network overlay architecture for the nsdl"

Connected through hyperedge HE-5 (induced by source paper "object re use exchange a resource centric approach"):
  with members:
    - "representing contextualized information in the nsdl"
    - "metadata aggregation and automated digital libraries a retrospective on the nsdl experience"

Connected through hyperedge HE-6 (induced by source paper "representing contextualized information in the nsdl"):
  with members:
    - "metadata aggregation and automated digital libraries a retrospective on the nsdl experience"
    - "core services in the architecture of the national digital library for science education nsdl"

Connected through hyperedge HE-7 (induced by source paper "an information network overlay architecture for the nsdl"):
  with members:
    - "flexible and extensible digital object and repository architecture fedora"
    - "the mellon fedora project digital library architecture meets xml and web services"
    - "core services in the architecture of the national digital library for science education nsdl"

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.DL(Digital Libraries)