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: "efficient isomorphism testing for a class of group extensions"
  Abstract: The group isomorphism problem asks whether two given groups are isomorphic or not. Whereas the case where both groups are abelian is well understood and can be solved efficiently, very little is known about the complexity of isomorphism testing for nonabelian groups. In this paper we study this problem for a class of groups corresponding to one of the simplest ways of constructing nonabelian groups from abelian groups: the groups that are extensions of an abelian group A by a cyclic group of order m. We present an efficient algorithm solving the group isomorphism problem for all the groups of this class such that the order of A is coprime with m. More precisely, our algorithm runs in time almost linear in the orders of the input groups and works in the general setting where the groups are given as black-boxes.

Connected through hyperedge HE-1 (induced by source paper "on the group and color isomorphism problems"):
  with members:
    - "polynomial time isomorphism test of groups that are tame extensions"
    - "bidirectional collision detection and faster deterministic isomorphism testing"
    - "algorithms for group isomorphism via group extensions and cohomology"

Connected through hyperedge HE-2 (induced by source paper "polynomial time isomorphism test of groups that are tame extensions"):
  with members:
    - "bidirectional collision detection and faster deterministic isomorphism testing"
    - "algorithms for group isomorphism via group extensions and cohomology"
    - "lie algebra conjugacy"
    - "deterministic polynomial time algorithms for matrix completion problems"

Connected through hyperedge HE-3 (induced by source paper "beating the generator enumeration bound for solvable group isomorphism"):
  with members:
    - "beating the generator enumeration bound for p group isomorphism"
    - "algorithms for group isomorphism via group extensions and cohomology"

Connected through hyperedge HE-4 (induced by source paper "beating the generator enumeration bound for p group isomorphism"):
  with members:
    - "beating the generator enumeration bound for solvable group isomorphism"
    - "bidirectional collision detection and faster deterministic isomorphism testing"
    - "algorithms for group isomorphism via group extensions and cohomology"
    - "breaking the n log n barrier for solvable group isomorphism"

Connected through hyperedge HE-5 (induced by source paper "algorithms for group isomorphism via group extensions and cohomology"):
  with members:
    - "bidirectional collision detection and faster deterministic isomorphism testing"
    - "complexity classes of equivalence problems revisited"
    - "lie algebra conjugacy"
    - "deterministic polynomial time algorithms for matrix completion problems"

Connected through hyperedge HE-6 (induced by source paper "bidirectional collision detection and faster deterministic isomorphism testing"):
  with members:
    - "breaking the n log n barrier for solvable group isomorphism"

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.DS(Data Structures and Algorithms)