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 supernodal formulation of vertex colouring with applications in course timetabling"
  Abstract: For many problems in scheduling and timetabling, the choice of a mathematical programming formulation is determined by the formulation of the graph colouring component. This paper briefly surveys seven known integer programming formulations of vertex colouring and introduces a new approach using “supernodes”. In the definition of George and McIntyre (SIAM J. Numer. Anal. 15(1):90–112, 1978 ), a “supernode” is a complete subgraph, within which every pair of vertices have the same neighbourhood outside of the subgraph. A polynomial-time algorithm for obtaining the best possible partition of an arbitrary graph into supernodes is given. This makes it possible to use any formulation of vertex multicolouring to encode vertex colouring. Results of empirical tests on benchmark instances in graph colouring (DIMACS) and timetabling (Udine Course Timetabling) are also provided and discussed. Copyright Springer Science+Business Media, LLC 2010

Connected through hyperedge HE-1 (induced by source paper "mobility offer allocations for corporate mobility as a service"):
  with members:
    - "route planning in transportation networks"

Connected through hyperedge HE-2 (induced by source paper "new integer linear programming models for the vertex coloring problem"):
  with members:
    - "compact layered drawings of general directed graphs"
    - "small maximal independent sets and faster exact graph coloring"

Connected through hyperedge HE-3 (induced by source paper "feature based tuning of simulated annealing applied to the curriculum based course timetabling problem"):
  with members:
    - "fairness in academic course timetabling"
    - "json2run a tool for experiment design a analysis"
    - "design engineering and experimental analysis of a simulated annealing approach to the post enrolment course timetabling problem"
    - "decomposition reformulation and diving in university course timetabling"

Connected through hyperedge HE-4 (induced by source paper "design engineering and experimental analysis of a simulated annealing approach to the post enrolment course timetabling problem"):
  with members:
    - "decomposition reformulation and diving in university course timetabling"

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)