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: "bottom up automata on data trees and vertical xpath"
  Abstract: A data tree is a tree whose every node carries a label from a finite alphabet and a datum from some infinite domain. We introduce a new model of automata over unranked data trees with a decidable emptiness problem. It is essentially a bottom-up alternating automaton with one register, enriched with epsilon-transitions that perform tests on the data values of the subtree. We show that it captures the expressive power of the vertical fragment of XPath —containing the child, descendant, parent and ancestor axes— obtaining thus a decision procedure for its satisfiability problem.

Connected through hyperedge HE-1 (induced by source paper "complexity results on register pushdown automata"):
  with members:
    - "alternating register automata on finite words and trees"
    - "on the freeze quantifier in constraint ltl decidability and complexity"

Connected through hyperedge HE-2 (induced by source paper "fo2 1 on data trees data tree automata and branching vector addition systems"):
  with members:
    - "an extension of data automata that captures xpath"

Connected through hyperedge HE-3 (induced by source paper "an automata theoretic approach to the verification of distributed algorithms"):
  with members:
    - "cycle detection in computation tree logic"
    - "propositional dynamic logic with converse and repeat for message passing systems"
    - "parameterized model checking of token passing systems"

Connected through hyperedge HE-4 (induced by source paper "alternating register automata on finite words and trees"):
  with members:
    - "relating timed and register automata"
    - "ackermannian and primitive recursive bounds with dickson s lemma"
    - "alternating automata on data trees and xpath satisfiability"
    - "ltl with the freeze quantifier and register automata"
    - "on the freeze quantifier in constraint ltl decidability and complexity"

Connected through hyperedge HE-5 (induced by source paper "tree regular model checking for lattice based automata"):
  with members:
    - "verifying recursive active documents with positive data tree rewriting"

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.DB(Databases)