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: "toroidal maps schnyder woods orthogonal surfaces and straight line representations"
  Abstract: A Schnyder wood is an orientation and coloring of the edges of a planar map satisfying a simple local property. We propose a generalization of Schnyder woods to graphs embedded on the torus with application to graph drawing. We prove several properties on this new object. Among all we prove that a graph embedded on the torus admits such a Schnyder wood if and only if it is an essentially 3-connected toroidal map. We show that these Schnyder woods can be used to embed the universal cover of an essentially 3-connected toroidal map on an infinite and periodic orthogonal surface. Finally we use this embedding to obtain a straight-line flat torus representation of any toroidal map in a polynomial size grid.

Connected through hyperedge HE-1 (induced by source paper "balanced schnyder woods for planar triangulations an experimental study with applications to graph drawing and graph separators"):
  with members:
    - "egalitarian graph orientations"
    - "encoding toroidal triangulations"

Connected through hyperedge HE-2 (induced by source paper "a bijection for essentially 4 connected toroidal triangulations"):
  with members:
    - "generalization of schnyder woods to orientable surfaces and applications"
    - "encoding toroidal triangulations"
    - "on the structure of schnyder woods on orientable surfaces"

Connected through hyperedge HE-3 (induced by source paper "encoding toroidal triangulations"):
  with members:
    - "generalization of schnyder woods to orientable surfaces and applications"
    - "on the structure of schnyder woods on orientable surfaces"
    - "structure of schnyder labelings on orientable surfaces"

Connected through hyperedge HE-4 (induced by source paper "on the structure of schnyder woods on orientable surfaces"):
  with members:
    - "encoding toroidal triangulations"

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)