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: "revealing comparative advantages in the backbone of science"
  Abstract: Mapping Science across countries is a challenging task in the field of Scientometrics. A number of efforts trying to cope with this task has been discussed in the state of the art, addressing this challenge by processing collections of scientific digital libraries and visualizing author-based measures (for instance, the h-index) or document-based measures (for instance, the averaged number of citations per document). A major drawback of these approaches is related to the presence of bias. The bigger the country, the higher the measure value. We explore the use of an econometric index to tackle this limitation, known as the Revealed Comparative Advantage measure (RCA). Using RCA, the diversity and ubiquity of each field of knowledge is mapped across countries. Then, a RCA-based proximity function is explored to visualize citation and h-index ubiquity. Science maps relating 27 knowledge areas and 237 countries are introduced using data crawled from Scimago that ranges from 1996 to 2011. Our results shows that the proposal is feasible and can be extended to ellaborate a global scientific production characterization.

Connected through hyperedge HE-1 (induced by source paper "the research space using the career paths of scholars to predict the evolution of the research output of individuals institutions and nations"):
  with members:
    - "how do you define and measure research productivity"
    - "science overlay maps a new tool for research policy and library management"

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)