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: "the mellon fedora project digital library architecture meets xml and web services"
  Abstract: The University of Virginia received a grant of $1,000,000 from the Andrew W. Mellon Foundation to enable the Library, in collaboration with Cornell University, to build a digital object repository system based on the Flexible Extensible Digital Object and Repository Architecture (Fedora). The new system demonstrates how distributed digital library architecture can be deployed using web-based technologies, including XML and Web services. The new system is designed to be a foundation upon which interoperable web-based digital libraries can be built. Virginia and collaborating partners in the US and UK will evaluate the system using a diverse set of digital collections. The software will be made available to the public as an open-source release.

Connected through hyperedge HE-1 (induced by source paper "when should i make preservation copies of myself"):
  with members:
    - "resurrecting my revolution using social link neighborhood in bringing context to the disappearing web"
    - "http mailbox asynchronous restful communication"
    - "analysis of graphs for digital preservation suitability"
    - "from random graph to small world by wandering"
    - "object re use exchange a resource centric approach"
    - "adore a modular standards based digital object repository"
    - "requirements for digital preservation systems a bottom up approach"

Connected through hyperedge HE-2 (induced by source paper "using first order logic to reason about policies"):
  with members:
    - "a formal foundation for xrml"
    - "a formal foundation for odrl"
    - "a logical reconstruction of spki"

Connected through hyperedge HE-3 (induced by source paper "fedora an architecture for complex objects and their relationships"):
  with members:
    - "flexible and extensible digital object and repository architecture fedora"
    - "policy carrying policy enforcing digital objects"
    - "adore a modular standards based digital object repository"
    - "an information network overlay architecture for the nsdl"

Connected through hyperedge HE-4 (induced by source paper "an information network overlay architecture for the nsdl"):
  with members:
    - "flexible and extensible digital object and repository architecture fedora"
    - "fedora an architecture for complex objects and their relationships"
    - "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)