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: "detecting the historical roots of tribology research a bibliometric analysis"
  Abstract: In this study, the historical roots of tribology (a sub-field of mechanical engineering and materials science) are investigated using a newly developed scientometric method called "Reference Publication Year Spectroscopy (RPYS)". The study is based on cited references (n = 577,472) in tribology research publications (n = 24,086). The Science Citation Index-Expanded (SCI-E) is used as data source. The results show that RPYS has the potential to identify the important publications: Most of the publications which have been identified in this study as highly cited (referenced) publications are landmark publications in the field of tribology.

Connected through hyperedge HE-1 (induced by source paper "identifying single influential publications in a research field new analysis opportunities of the crexplorer"):
  with members:
    - "climate change research in view of bibliometrics"
    - "smart girls versus sleeping beauties in the sciences the identification of instant and delayed recognition by using the citation angle"
    - "introducing citedreferencesexplorer crexplorer a program for reference publication year spectroscopy with cited references standardization"
    - "new features of citedreferencesexplorer crexplorer"
    - "citation score normalized by cited references csncr the introduction of a new citation impact indicator"
    - "a review of the literature on citation impact indicators"
    - "growth rates of modern science a bibliometric analysis based on the number of publications and cited references"
    - "citnetexplorer a new software tool for analyzing and visualizing citation networks"

Connected through hyperedge HE-2 (induced by source paper "patent citation spectroscopy pcs algorithmic retrieval of landmark patents"):
  with members:
    - "strategic intelligence on emerging technologies scientometric overlay mapping"
    - "citation algorithms for identifying research milestones driving biomedical innovation"
    - "citations indicators of quality the impact fallacy"
    - "detecting the historical roots of research fields by reference publication year spectroscopy rpys"
    - "referenced publication years spectroscopy applied to imetrics scientometrics journal of informetrics and a relevant subset of jasist"

Connected through hyperedge HE-3 (induced by source paper "rpys i o a web based tool for the historiography and visualization of citation classics sleeping beauties and research fronts"):
  with members:
    - "introducing citedreferencesexplorer crexplorer a program for reference publication year spectroscopy with cited references standardization"
    - "identification of long term concept symbols among citations can documents be clustered in terms of common intellectual histories"
    - "referenced publication year spectroscopy rpys and algorithmic historiography the bibliometric reconstruction of andras schubert s œuvre"
    - "citnetexplorer a new software tool for analyzing and visualizing citation networks"
    - "detecting the historical roots of research fields by reference publication year spectroscopy rpys"
    - "referenced publication years spectroscopy applied to imetrics scientometrics journal of informetrics and a relevant subset of jasist"

Connected through hyperedge HE-4 (induced by source paper "citation algorithms for identifying research milestones driving biomedical innovation"):
  with members:
    - "a triple helix model of medical innovation supply demand and technological capabilities in terms of medical subject headings"
    - "introducing citedreferencesexplorer crexplorer a program for reference publication year spectroscopy with cited references standardization"
    - "identification of long term concept symbols among citations can documents be clustered in terms of common intellectual histories"
    - "growth rates of modern science a bibliometric analysis based on the number of publications and cited references"
    - "detecting the historical roots of research fields by reference publication year spectroscopy rpys"
    - "referenced publication years spectroscopy applied to imetrics scientometrics journal of informetrics and a relevant subset of jasist"

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)