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: "automatic structures richness and limitations"
  Abstract: We study the existence of automatic presentations for various algebraic#N#structures. An automatic presentation of a structure is a description of the#N#universe of the structure by a regular set of words, and the interpretation of#N#the relations by synchronised automata. Our first topic concerns characterising#N#classes of automatic structures. We supply a characterisation of the automatic#N#Boolean algebras, and it is proven that the free Abelian group of infinite#N#rank, as well as certain Fraisse limits, do not have automatic presentations.#N#In particular, the countably infinite random graph and the random partial order#N#do not have automatic presentations. Furthermore, no infinite integral domain#N#is automatic. Our second topic is the isomorphism problem. We prove that the#N#complexity of the isomorphism problem for the class of all automatic structures#N#is \Sigma_1^1-complete.

Connected through hyperedge HE-1 (induced by source paper "automatic supermartingales acting on sequences"):
  with members:
    - "automatic kolmogorov complexity and normality revisited"
    - "phase transition and strong predictability"

Connected through hyperedge HE-2 (induced by source paper "comparing the power of advice strings a notion of complexity for infinite words"):
  with members:
    - "a myhill nerode theorem for automata with advice"

Connected through hyperedge HE-3 (induced by source paper "tree automatic well founded trees"):
  with members:
    - "word automaticity of tree automatic scattered linear orderings is decidable"
    - "automatic structures of bounded degree revisited"

Connected through hyperedge HE-4 (induced by source paper "structures without scattered automatic presentation"):
  with members:
    - "tree automatic well founded trees"
    - "the rank of tree automatic linear orderings"

Connected through hyperedge HE-5 (induced by source paper "isomorphisms of scattered automatic linear orders"):
  with members:
    - "the rank of tree automatic linear orderings"
    - "isomorphism of regular trees and words"

Connected through hyperedge HE-6 (induced by source paper "isomorphism of regular trees and words"):
  with members:
    - "isomorphisms of scattered automatic linear orders"
    - "faster fully compressed pattern matching by recompression"
    - "representing small ordinals by finite automata"
    - "algebraic linear orderings"
    - "the isomorphism problem on classes of automatic structures"

Connected through hyperedge HE-7 (induced by source paper "the isomorphism problem for omega automatic trees"):
  with members:
    - "the isomorphism problem on classes of automatic structures"
    - "highly undecidable problems for infinite computations"

Connected through hyperedge HE-8 (induced by source paper "the isomorphism problem on classes of automatic structures"):
  with members:
    - "cardinality and counting quantifiers on omega automatic structures"

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.DM(Discrete Mathematics)