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 constraint propagation engines"
  Abstract: This paper presents a model and implementation techniques for speeding up constraint propagation. Three fundamental approaches to improving constraint propagation based on propagators as implementations of constraints are explored: keeping track of which propagators are at fixpoint, choosing which propagator to apply next, and how to combine several propagators for the same constraint. We show how idempotence reasoning and events help track fixpoints more accurately. We improve these methods by using them dynamically (taking into account current domains to improve accuracy). We define priority-based approaches to choosing a next propagator and show that dynamic priorities can improve propagation. We illustrate that the use of multiple propagators for the same constraint can be advantageous with priorities, and introduce staged propagators that combine the effects of multiple propagators with priorities for greater efficiency.

Connected through hyperedge HE-1 (induced by source paper "spacetime programming a synchronous language for composable search strategies"):
  with members:
    - "eclipse from lp to clp"
    - "on the implementation of gnu prolog"
    - "the essence of constraint propagation"

Connected through hyperedge HE-2 (induced by source paper "ite a lightweight implementation of stratified reasoning for constructive logical operators"):
  with members:
    - "time aware test case execution scheduling for cyber physical systems"
    - "the ultrametric constraint and its application to phylogenetics"

Connected through hyperedge HE-3 (induced by source paper "stratified constructive disjunction and negation in constraint programming"):
  with members:
    - "time aware test case execution scheduling for cyber physical systems"
    - "the ultrametric constraint and its application to phylogenetics"

Connected through hyperedge HE-4 (induced by source paper "constraint answer set solver ezcsp and why integration schemas matter"):
  with members:
    - "the language features and architecture of b prolog"
    - "a translational approach to constraint answer set solving"
    - "sicstus prolog the first 25 years"
    - "weight constraints as nested expressions"
    - "stable models and an alternative logic programming paradigm"

Connected through hyperedge HE-5 (induced by source paper "predicate logic as a modeling language modeling and solving some machine learning and data mining problems with idp3"):
  with members:
    - "predicate logic as a modelling language the idp system"
    - "lazy model expansion interleaving grounding with search"
    - "a prototype of a knowledge based programming environment"
    - "xsb extending prolog with tabled logic programming"
    - "constraint propagation for first order logic and inductive definitions"
    - "grounding fo and fo id with bounds"
    - "the dlv system for knowledge representation and reasoning"
    - "well founded and stable semantics of logic programs with aggregates"

Connected through hyperedge HE-6 (induced by source paper "ntccrt a concurrent constraint framework for real time interaction extended version"):
  with members:
    - "process ordering in a process calculus for spatially explicit ecological models"
    - "mean field semantics for a process calculus for spatially explicit ecological models"
    - "a model for interactive scores with temporal constraints and conditional branching"
    - "structured interactive music scores"
    - "an extension of interactive scores for multimedia scenarios with temporal relations for micro and macro controls"

Connected through hyperedge HE-7 (induced by source paper "towards non threaded concurrent constraint programming for implementing multimedia interaction systems"):
  with members:
    - "process ordering in a process calculus for spatially explicit ecological models"
    - "mean field semantics for a process calculus for spatially explicit ecological models"
    - "a model for interactive scores with temporal constraints and conditional branching"
    - "structured interactive music scores"
    - "an extension of interactive scores for multimedia scenarios with temporal relations for micro and macro controls"

Connected through hyperedge HE-8 (induced by source paper "gelisp a library to represent musical csps and search strategies"):
  with members:
    - "a model for interactive scores with temporal constraints and conditional branching"
    - "structured interactive music scores"
    - "an extension of interactive scores for multimedia scenarios with temporal relations for micro and macro controls"
    - "towards non threaded concurrent constraint programming for implementing multimedia interaction systems"

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.AI(Artificial Intelligence)