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: "algebraic recognizability of regular tree languages"
  Abstract: We propose a new algebraic framework to discuss and classify recognizable tree languages, and to characterize interesting classes of such languages. Our algebraic tool, called preclones, encompasses the classical notion of syntactic Sigma-algebra or minimal tree automaton, but adds new expressivity to it. The main result in this paper is a variety theorem \`{a} la Eilenberg, but we also discuss important examples of logically defined classes of recognizable tree languages, whose characterization and decidability was established in recent papers (by Benedikt and S\'{e}goufin, and by Bojanczyk and Walukiewicz) and can be naturally formulated in terms of pseudovarieties of preclones. Finally, this paper constitutes the foundation for another paper by the same authors, where first-order definable tree languages receive an algebraic characterization.

Connected through hyperedge HE-1 (induced by source paper "wreath products of forest algebras with applications to tree logics"):
  with members:
    - "piecewise testable tree languages"
    - "a decidable characterization of locally testable tree languages"
    - "tree languages defined in first order logic with one quantifier alternation"
    - "two way unary temporal logic over trees"
    - "logics for unranked trees an overview"

Connected through hyperedge HE-2 (induced by source paper "a decidable characterization of locally testable tree languages"):
  with members:
    - "piecewise testable tree languages"
    - "tree languages defined in first order logic with one quantifier alternation"
    - "two way unary temporal logic over trees"

Connected through hyperedge HE-3 (induced by source paper "algebraic characterization of logically defined tree languages"):
  with members:
    - "piecewise testable tree languages"
    - "tree languages defined in first order logic with one quantifier alternation"
    - "two way unary temporal logic over trees"
    - "algebraic recognizability of languages"

Connected through hyperedge HE-4 (induced by source paper "logic meets algebra the case of regular languages"):
  with members:
    - "algebraic recognizability of languages"
    - "arithmetic first order logic and counting quantifiers"
    - "the descriptive complexity approach to logcfl"

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)