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: "complexity results for rainbow matchings"
  Abstract: A rainbow matching in an edge-colored graph is a matching whose edges have distinct colors. We address the complexity issue of the following problem, max rainbow matching: Given an edge-colored graph G, how large is the largest rainbow matching in G? We present several sharp contrasts in the complexity of this problem.We show, among others, thatmax rainbow matching can be approximated by a polynomial algorithm with approximation ratio 2 / 3 - e .max rainbow matching is APX-complete, even when restricted to properly edge-colored linear forests without a 5-vertex path, and is solvable in polynomial time for edge-colored forests without a 4-vertex path.max rainbow matching is APX-complete, even when restricted to properly edge-colored trees without an 8-vertex path, and is solvable in polynomial time for edge-colored trees without a 7-vertex path.max rainbow matching is APX-complete, even when restricted to properly edge-colored paths. These results provide a dichotomy theorem for the complexity of the problem on forests and trees in terms of forbidding paths. The latter is somewhat surprising, since, to the best of our knowledge, no (unweighted) graph problem prior to our result is known to be NP-hard for simple paths.We also address the parameterized complexity of the problem.

Connected through hyperedge HE-1 (induced by source paper "keeping your friends close land allocation with friends"):
  with members:
    - "graphical one sided markets"
    - "the impossibility of extending random dictatorship to weak preferences"
    - "efficiency of truthful and symmetric mechanisms in one sided matching"
    - "social welfare in one sided matchings random priority and beyond"
    - "peer effects and stability in matching markets"

Connected through hyperedge HE-2 (induced by source paper "integrality gaps for bounded color matchings"):
  with members:
    - "a birthday repetition theorem and complexity of approximating dense csps"
    - "lift and round to improve weighted completion time on unrelated machines"
    - "generalized hypergraph matching via iterated packing and local ratio"
    - "on integrality ratios for asymmetric tsp in the sherali adams hierarchy"
    - "sparsest cut on bounded treewidth graphs algorithms and hardness results"
    - "iterative packing for demand and hypergraph matching"
    - "approximating sparsest cut in graphs of bounded treewidth"

Connected through hyperedge HE-3 (induced by source paper "designing deterministic polynomial space algorithms by color coding multivariate polynomials"):
  with members:
    - "directed hamiltonicity and out branchings via generalized laplacians"
    - "spotting trees with few leaves"
    - "fast algorithms for parameterized problems with relaxed disjointness constraints"
    - "representative families a unified tradeoff based approach"
    - "mixing color coding related techniques"
    - "abusing the tutte matrix an algebraic instance compression for the k set cycle problem"
    - "narrow sieves for parameterized paths and packings"
    - "determinant sums for undirected hamiltonicity"

Connected through hyperedge HE-4 (induced by source paper "group activity selection on social networks"):
  with members:
    - "fairly allocating contiguous blocks of indivisible items"
    - "on parameterized complexity of group activity selection problems on social networks"
    - "fair division of a graph"
    - "hedonic games with graph restricted communication"
    - "group activity selection problem"
    - "core stability in hedonic coalition formation"

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)