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: "a generalized matrix tree theorem for pfaffian pairs"
  Abstract: The matrix-tree theorem counts the number of spanning trees of undirected graphs as well as the number of column bases of totally unimodular matrices. Extending this theorem, Webb (2004) introduced the notion of Pfaffian pairs as a pair of totally unimodular matrices for which counting of their common bases is tractable. This paper consolidates a list of combinatorial structures that can be represented as Pfaffian pairs. This includes spanning trees, Euler tours in four-regular digraphs, arborescences, and perfect matchings in $K_{3,3}$-free bipartite graphs. We also present a strongly polynomial-time algorithm to count maximum weight common bases in weighted Pfaffian pairs. Our algorithm makes use of Frank's weight splitting lemma on the weighted matroid intersection. We further consider the counting problem for Pfaffian pairs under group-label constraints.

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)