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: "copar an efficient generic partition refiner"
  Abstract: Partition refinement is a method for minimizing automata and transition systems of various types. We present a tool implementing a recently developed partition refinement algorithm that is generic in the transition type of the given system and typically runs in time either $\mathcal{O}(m\cdot \log n)$ or $\mathcal{O}(m\cdot \log n\cdot\log m)$ for systems with $m$ edges and $n$ states. This matches the runtime of the best known algorithms for several fixed types of systems, e.g. deterministic automata as well as ordinary, weighted, and probabilistic (labelled) transition systems, and in the case of weighted systems over non-cancellative monoids, such as (the additive monoid of) the tropical semiring, even improves the asymptotic runtime. Genericity is achieved by modelling transition types as endofunctors on sets and state-based systems as coalgebras. In addition to thus obtaining an efficient partion refiner for the mentioned types of systems, we demonstrate how the user can quickly obtain a partition refiner for new types of systems by composing pre-implemented basic functors, and how the tool can easily be extended with new basic functors by implementing a refinement interface.

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)