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: "how have the eastern european countries of the former warsaw pact developed since 1990 a bibliometric study"
  Abstract: Did the demise of the Soviet Union in 1991 influence the scientific performance of the researchers in Eastern European countries? Did this historical event affect international collaboration by researchers from the Eastern European countries with those of Western countries? Did it also change international collaboration among researchers from the Eastern European countries? Trying to answer these questions, this study aims to shed light on international collaboration by researchers from the Eastern European countries (Russia, Ukraine, Belarus, Moldova, Bulgaria, the Czech Republic, Hungary, Poland, Romania and Slovakia). The number of publications and normalized citation impact values are compared for these countries based on InCites (Thomson Reuters), from 1981 up to 2011. The international collaboration by researchers affiliated to institutions in Eastern European countries at the time points of 1990, 2000 and 2011 was studied with the help of Pajek and VOSviewer software, based on data from the Science Citation Index (Thomson Reuters). Our results show that the breakdown of the communist regime did not lead, on average, to a huge improvement in the publication performance of the Eastern European countries and that the increase in international co-authorship relations by the researchers affiliated to institutions in these countries was smaller than expected. Most of the Eastern European countries are still subject to changes and are still awaiting their boost in scientific development.

Connected through hyperedge HE-1 (induced by source paper "the evolution of sentiment analysis a review of research topics venues and top cited papers"):
  with members:
    - "the journal coverage of web of science and scopus a comparative analysis"
    - "measuring praise and criticism inference of semantic orientation from association"
    - "thumbs up or thumbs down semantic orientation applied to unsupervised classification of reviews"
    - "thumbs up sentiment classification using machine learning techniques"

Connected through hyperedge HE-2 (induced by source paper "a spatial scientometric analysis of the publication output of cities worldwide"):
  with members:
    - "mapping spatial and temporal changes of global corporate research and development activities by conducting a bibliometric analysis"
    - "exploring the position of cities in global corporate research and development a bibliometric analysis by two different geographical approaches"
    - "the journal coverage of web of science and scopus a comparative analysis"
    - "mapping excellence in the geography of science an approach based on scopus data"
    - "globalisation of science in kilometres"
    - "the detection of hot regions in the geography of science a visualization approach by using density maps"
    - "mapping the geography of science distribution patterns and networks of relations among cities and institutes"

Connected through hyperedge HE-3 (induced by source paper "the european union china and the united states in the top 1 and top 10 layers of most frequently cited publications competition and collaborations"):
  with members:
    - "how are excellent highly cited papers defined in bibliometrics a quantitative analysis of the literature"
    - "brics countries and scientific excellence a bibliometric analysis of most frequently cited papers"
    - "caveats for using statistical significance tests in research assessments"
    - "the use of percentiles and percentile rank classes in the analysis of bibliometric data opportunities and limits"
    - "the leiden ranking 2011 2012 data collection indicators and interpretation"
    - "publish or patent bibliometric evidence for empirical trade offs in national funding strategies"
    - "testing differences statistically with the leiden ranking"
    - "world shares of publications of the usa eu 27 and china compared and predicted using the new interface of the web of science versus scopus"

Connected through hyperedge HE-4 (induced by source paper "brics countries and scientific excellence a bibliometric analysis of most frequently cited papers"):
  with members:
    - "growth rates of modern science a bibliometric analysis based on the number of publications and cited references"
    - "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 percentile based approach should be preferred for calculating normalized citation impact values an empirical comparison of five approaches including a newly developed citation rank approach p100"
    - "how to improve the prediction based on citation impact percentiles for years shortly after the publication date"
    - "the use of percentiles and percentile rank classes in the analysis of bibliometric data opportunities and limits"
    - "remaining problems with the new crown indicator mncs of the cwts"

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)