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: "research excellence milestones of bric and n 11 countries"
  Abstract: While scientific performance is an important aspect of a stable and healthy economy, measures for it have yet to gain their place in economic country profiles. As useful indicators for this performance dimension, this paper introduces the concept of milestones for research excellence, as points of transition to higher-level contributions at the leading edge of science. The proposed milestones are based on two indicators associated with research excellence, the impact vitality profile and the production of review type publications, both applied to a country's publications in the top journals Nature and Science. The milestones are determined for two distinct groups of emerging market economies: the BRIC countries, which outperformed the relative growth expected at their identification in 2001, and the N-11 or Next Eleven countries, identified in 2005 as potential candidates for a BRIC-like evolution. Results show how these two groups at different economic levels can be clearly distinguished based on the research milestones, indicating a potential utility as parameters in an economic context.

Connected through hyperedge HE-1 (induced by source paper "recent developments in china u s cooperation in science"):
  with members:
    - "brics countries and scientific excellence a bibliometric analysis of most frequently cited papers"
    - "the european union china and the united states in the top 1 and top 10 layers of most frequently cited publications competition and collaborations"
    - "which cities produce excellent papers worldwide more than can be expected a new mapping approach using google maps based on statistical significance testing"
    - "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)