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 research fields by reference publication year spectroscopy rpys"
  Abstract: We introduce the quantitative method named "reference publication year spectroscopy" (RPYS). With this method one can determine the historical roots of research fields and quantify their impact on current research. RPYS is based on the analysis of the frequency with which references are cited in the publications of a specific research field in terms of the publication years of these cited references. The origins show up in the form of more or less pronounced peaks mostly caused by individual publications which are cited particularly frequently. In this study, we use research on graphene and on solar cells to illustrate how RPYS functions, and what results it can deliver.

Connected through hyperedge HE-1 (induced by source paper "how to identify the roots of broad research topics and fields the introduction of rpys sampling using the example of climate change research"):
  with members:
    - "climate change research in view of bibliometrics"
    - "introducing citedreferencesexplorer crexplorer a program for reference publication year spectroscopy with cited references standardization"
    - "growth rates of modern science a bibliometric analysis based on the number of publications and cited references"
    - "referenced publication years spectroscopy applied to imetrics scientometrics journal of informetrics and a relevant subset of jasist"

Connected through hyperedge HE-2 (induced by source paper "discovering seminal works with marker papers"):
  with members:
    - "telling the early story of solar energy meteorology by applying co citation reference publication year spectroscopy"
    - "identifying single influential publications in a research field new analysis opportunities of the crexplorer"
    - "climate change research in view of bibliometrics"
    - "citnetexplorer a new software tool for analyzing and visualizing citation networks"

Connected through hyperedge HE-3 (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"
    - "detecting the historical roots of tribology research a bibliometric analysis"
    - "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"

Connected through hyperedge HE-4 (induced by source paper "intermediacy of publications"):
  with members:
    - "accuracy of citation data in web of science and scopus"
    - "which type of citation analysis generates the most accurate taxonomy of scientific and technical knowledge"
    - "tracing technological development trajectories a genetic knowledge persistence based main path approach"
    - "introducing citedreferencesexplorer crexplorer a program for reference publication year spectroscopy with cited references standardization"
    - "citnetexplorer a new software tool for analyzing and visualizing citation networks"
    - "a new methodology for constructing a publication level classification system of science"
    - "efficient algorithms for citation network analysis"

Connected through hyperedge HE-5 (induced by source paper "bibliometric approximation of a scientific specialty by combining key sources title words authors and references"):
  with members:
    - "4d specialty approximation ability to distinguish between related specialties"
    - "investigation of partition cells as a structural basis suitable for assessments of individual scientists"
    - "the operationalization of fields as wos subject categories wcs in evaluative bibliometrics the cases of library and information science and science technology studies"
    - "citation analysis may severely underestimate the impact of clinical research as compared to basic research"
    - "partition based field normalization an approach to highly specialized publication records"
    - "a new methodology for constructing a publication level classification system of science"
    - "the structure and dynamics of co citation clusters a multiple perspective co citation analysis"

Connected through hyperedge HE-6 (induced by source paper "data mining the foundational patents of photovoltaic materials an application of patent citation spectroscopy"):
  with members:
    - "strategic intelligence on emerging technologies scientometric overlay mapping"
    - "patent citation spectroscopy pcs algorithmic retrieval of landmark patents"
    - "citation algorithms for identifying research milestones driving biomedical innovation"
    - "introducing citedreferencesexplorer crexplorer a program for reference publication year spectroscopy with cited references standardization"
    - "patents as instruments for exploring innovation dynamics geographic and technological perspectives on photovoltaic cells"
    - "publish or patent bibliometric evidence for empirical trade offs in national funding strategies"

Connected through hyperedge HE-7 (induced by source paper "reference publication year spectroscopy rpys of eugene garfield s publications"):
  with members:
    - "introducing citedreferencesexplorer crexplorer a program for reference publication year spectroscopy with cited references standardization"
    - "new features of citedreferencesexplorer crexplorer"
    - "citnetexplorer a new software tool for analyzing and visualizing citation networks"
    - "eugene garfield and algorithmic historiography co words co authors and journal names"

Connected through hyperedge HE-8 (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 tribology research a bibliometric analysis"
    - "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)