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: "xperm fast index canonicalization for tensor computer algebra"
  Abstract: Abstract   We present a very fast implementation of the Butler–Portugal algorithm for index canonicalization with respect to permutation symmetries. It is called  xPerm , and has been written as a combination of a  Mathematica  package and a C subroutine. The latter performs the most demanding parts of the computations and can be linked from any other program or computer algebra system. We demonstrate with tests and timings the effectively polynomial performance of the Butler–Portugal algorithm with respect to the number of indices, though we also show a case in which it is exponential. Our implementation handles generic tensorial expressions with several dozen indices in hundredths of a second, or one hundred indices in a few seconds, clearly outperforming all other current canonicalizers. The code has been already under intensive testing for several years and has been essential in recent investigations in large-scale tensor computer algebra.    Program summary   Program title:  xPerm   Catalogue identifier:  AEBH_v1_0   Program summary URL:   http://cpc.cs.qub.ac.uk/summaries/AEBH_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.:  93 582   No. of bytes in distributed program, including test data, etc.:  1 537 832   Distribution format:  tar.gz   Programming language:  C and Mathematica (version 5.0 or higher)   Computer:  Any computer running C and Mathematica (version 5.0 or higher)   Operating system:  Linux, Unix, Windows XP, MacOS   RAM::  20 Mbyte   Word size:  64 or 32 bits   Classification:  1.5, 5   Nature of problem:  Canonicalization of indexed expressions with respect to permutation symmetries.   Solution method:  The Butler–Portugal algorithm.   Restrictions:  Multiterm symmetries are not considered.   Running time:  A few seconds with generic expressions of up to 100 indices. The  xPermDoc.nb  notebook supplied with the distribution takes approximately one and a half hours to execute in full.

Connected through hyperedge HE-1 (induced by source paper "faster tensor canonicalization"):
  with members:
    - "riemann tensor polynomial canonicalization by graph algebra extension"
    - "introduction to redberry a computer algebra system designed for tensor manipulation"
    - "the invar tensor package differential invariants of riemann"
    - "cadabra a field theory motivated symbolic computer algebra system"

Connected through hyperedge HE-2 (induced by source paper "riemann tensor polynomial canonicalization by graph algebra extension"):
  with members:
    - "xtras a field theory inspired xact package for mathematica"
    - "the invar tensor package"
    - "atensor reduce program for tensor simplification"

Connected through hyperedge HE-3 (induced by source paper "xtras a field theory inspired xact package for mathematica"):
  with members:
    - "the invar tensor package differential invariants of riemann"
    - "the invar tensor package"

Connected through hyperedge HE-4 (induced by source paper "introduction to redberry a computer algebra system designed for tensor manipulation"):
  with members:
    - "tensor computations in computer algebra systems"
    - "practical graph isomorphism ii"
    - "cadabra a field theory motivated symbolic computer algebra system"
    - "introduction to the ginac framework for symbolic computation within the c programming language"

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)