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: "academic collaboration rates and citation associations vary substantially between countries and fields"
  Abstract: Research collaboration is promoted by governments and research funders but if the relative prevalence and merits of collaboration vary internationally different national and disciplinary strategies may be needed to promote it. This study compares the team size and field normalised citation impact of research across all 27 Scopus broad fields in the ten countries with the most journal articles indexed in Scopus 2008-2012. The results show that team size varies substantially by discipline and country, with Japan (4.2) having two thirds more authors per article than the UK (2.5). Solo authorship is rare in China (4%) but common in the UK (27%). Whilst increasing team size associates with higher citation impact in almost all countries and fields, this association is much weaker in China than elsewhere. There are also field differences in the association between citation impact and collaboration. For example, larger team sizes in the Business, Management & Accounting category do not seem to associate with greater research impact, and for China and India, solo authorship associates with higher citation impact. Overall, there are substantial international and field differences in the extent to which researchers collaborate and the extent to which collaboration associates with higher citation impact.

Connected through hyperedge HE-1 (induced by source paper "gender disparities in international research collaboration a large scale bibliometric study of 25 000 university professors"):
  with members:
    - "a gender analysis of top scientists collaboration behavior evidence from italy"
    - "the collaboration behavior of top scientists"
    - "comparison of research productivity of italian and norwegian professors and universities"
    - "gender differences in scientific collaborations women are more egalitarian than men"
    - "gender differences in research collaboration"
    - "are researchers that collaborate more at the international level top performers an investigation on the italian university system"
    - "the relationship between scientists research performance and the degree of internationalization of their research"
    - "the contribution of star scientists to overall sex differences in research productivity"

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)