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: "diamond free degree sequences"
  Abstract: While attempting to classify partial linear spaces produced#R##N#during the execution of an extension of Stinson's hill-climbing algorithm#R##N#a new problem arises, that of generating all graphical degree sequences#R##N#that are diamond-free (i.e. have no diamond as subgraph) and satisfy ad-#R##N#ditional constraints. We formalize this new problem, propose a constraint#R##N#programming solution and list all satisfying degree sequences of length 8#R##N#to 16 inclusive.

Connected through hyperedge HE-1 (induced by source paper "bfs enumeration for breaking symmetries in graphs"):
  with members:
    - "breaking symmetries in graph search with canonizing sets"

Connected through hyperedge HE-2 (induced by source paper "computing the ramsey number r 4 3 3 using abstraction and symmetry breaking"):
  with members:
    - "boolean equi propagation for concise and efficient sat encodings of combinatorial problems"
    - "satisfiability and computing van der waerden numbers"

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)