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: "intersection graphs an introduction"
  Abstract: Intersection graphs are very important in both the oretical as well as application point of view. Depending on the geometrical represe ntation, different type of intersection graphs are defined. Among them interval, circular-a rc, permutation, trapezoid, chordal, disk, circle graphs are more important. In this art icle, a brief introduction of each of these intersection graphs is given. Some basic properties and algorithmic status of few problems on these graphs are cited. This article will help t o the beginners to start work in this direction. Since the article contains a lot of info rmation in a compact form it is also useful for the expert researchers too.

Connected through hyperedge HE-1 (induced by source paper "low congestion shortcut and graph parameters"):
  with members:
    - "time message trade offs in distributed algorithms"
    - "round and message optimal distributed graph algorithms"
    - "minor excluded network families admit fast distributed algorithms"
    - "distributed treewidth computation"
    - "new distributed algorithms in almost mixing time via transformations from parallel algorithms"
    - "faster distributed shortest path approximations via shortcuts"
    - "near linear lower bounds for distributed distance computations even in sparse networks"
    - "low congestion shortcuts without embedding"

Connected through hyperedge HE-2 (induced by source paper "scheduling algorithm to select k optimal programme slots in television channels a graph theoretic approach"):
  with members:
    - "an cal o n 2 log n algorithm for the weighted stable set problem in claw free graphs"

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)