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: "the invar tensor package"
  Abstract: Abstract   The  Invar  package is introduced, a fast manipulator of generic scalar polynomial expressions formed from the Riemann tensor of a four-dimensional metric-compatible connection. The package can maximally simplify any polynomial containing tensor products of up to seven Riemann tensors within seconds. It has been implemented both in Mathematica and Maple algebraic systems.    Program summary   Program title: Invar Tensor Package   Catalogue identifier: ADZK_v1_0   Program summary URL:  http://cpc.cs.qub.ac.uk/summaries/ADZK_v1_0.html    Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland   Licensing provisions: Standard CPC licence,  http://cpc.cs.qub.ac.uk/licence/licence.html    No. of lines in distributed program, including test data, etc.:  136 240   No. of bytes in distributed program, including test data, etc.: 2 711 923   Distribution format: tar.gz   Programming language: Mathematica and Maple   Computer: Any computer running Mathematica versions 5.0 to 5.2 or Maple versions 9 and 10   Operating system: Linux, Unix, Windows XP   RAM: 30 Mb   Word size: 64 or 32 bits   Classification: 5   External routines: The Mathematica version requires the xTensor and xPerm packages. These are freely available at  http://metric.iem.csic.es/Martin-Garcia/xAct    Nature of problem: Manipulation and simplification of tensor expressions. Special attention on simplifying scalar polynomial expressions formed from the Riemann tensor on a four-dimensional metric-compatible manifold.   Solution method: Algorithms of computational group theory to simplify expressions with tensors that obey permutation symmetries. Tables of syzygies of the scalar invariants of the Riemann tensor.   Restrictions: The present versions do not fully address the problem of reducing differential invariants or monomials of the Riemann tensor with free indices.   Running time: Less than a second to fully reduce a monomial of the Riemann tensor of degree 7 in terms of independent invariants.

Connected through hyperedge HE-1 (induced by source paper "riemann tensor polynomial canonicalization by graph algebra extension"):
  with members:
    - "xtras a field theory inspired xact package for mathematica"
    - "xperm fast index canonicalization for tensor computer algebra"
    - "atensor reduce program for tensor simplification"

Connected through hyperedge HE-2 (induced by source paper "xtras a field theory inspired xact package for mathematica"):
  with members:
    - "the invar tensor package differential invariants of riemann"
    - "xperm fast index canonicalization for tensor computer algebra"

Connected through hyperedge HE-3 (induced by source paper "xperm fast index canonicalization for tensor computer algebra"):
  with members:
    - "cadabra a field theory motivated symbolic computer algebra system"

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.SC(Symbolic Computation)