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: "on brambles grid like minors and parameterized intractability of monadic second order logic"
  Abstract: Brambles were introduced as the dual notion to treewidth, one of the most central concepts of the graph minor theory of Robertson and Seymour. Recently, Grohe and Marx showed that there are graphs G, in which every bramble of order larger than the square root of the treewidth is of exponential size in |G|. On the positive side, they show the existence of polynomial-sized brambles of the order of the square root of the treewidth, up to log factors. We provide the first polynomial time algorithm to construct a bramble in general graphs and achieve this bound, up to log-factors. We use this algorithm to construct grid-like minors, a replacement structure for grid-minors recently introduced by Reed and Wood, in polynomial time. Using the grid-like minors, we introduce the notion of a perfect bramble and an algorithm to find one in polynomial time. Perfect brambles are brambles with a particularly simple structure and they also provide us with a subgraph that has bounded degree and still large treewidth; we use them to obtain a meta-theorem on deciding certain parameterized subgraph-closed problems on general graphs in time singly exponential in the parameter. #R##N#The second part of our work deals with providing a lower bound to Courcelle's famous theorem, stating that every graph property that can be expressed by a sentence in monadic second-order logic (MSO), can be decided by a linear time algorithm on classes of graphs of bounded treewidth. Using our results from the first part of our work we establish a strong lower bound for tractability of MSO on classes of colored graphs.

Connected through hyperedge HE-1 (induced by source paper "model checking for successor invariant first order formulas on graph classes of bounded expansion"):
  with members:
    - "a new perspective on fo model checking of dense graph classes"
    - "the generalised colouring numbers on classes of bounded expansion"
    - "order invariance on decomposable structures"
    - "successor invariant first order logic on graphs with excluded topological subgraphs"
    - "fo model checking of interval graphs"
    - "deciding first order properties of nowhere dense graphs"
    - "structure theorem and isomorphism test for graphs with excluded topological subgraphs"
    - "lower bounds for the complexity of monadic second order logic"

Connected through hyperedge HE-2 (induced by source paper "the directed grid theorem"):
  with members:
    - "bidimensionality and kernels"
    - "polynomial bounds for the grid minor theorem"
    - "the planar directed k vertex disjoint paths problem is fixed parameter tractable"
    - "directed nowhere dense classes of graphs"
    - "bidimensionality and eptas"
    - "finding topological subgraphs is fixed parameter tractable"

Connected through hyperedge HE-3 (induced by source paper "deciding first order properties of nowhere dense graphs"):
  with members:
    - "fo model checking on posets of bounded width"
    - "lower bounds for the complexity of monadic second order logic"
    - "domination problems in nowhere dense classes of graphs"
    - "algorithmic meta theorems"
    - "homomorphism preservation on quasi wide classes"
    - "deciding first order properties of locally tree decomposable structures"
    - "fixed parameter tractability definability and model checking"

Connected through hyperedge HE-4 (induced by source paper "polynomial bounds for the grid minor theorem"):
  with members:
    - "degree 3 treewidth sparsifiers"
    - "maximum edge disjoint paths in k sums of graphs"
    - "large treewidth graph decompositions and applications"
    - "a polylogarithimic approximation algorithm for edge disjoint paths with congestion 2"
    - "routing in undirected graphs with constant congestion"
    - "a graph reduction step preserving element connectivity and applications"

Connected through hyperedge HE-5 (induced by source paper "large treewidth graph decompositions and applications"):
  with members:
    - "a polylogarithimic approximation algorithm for edge disjoint paths with congestion 2"
    - "routing in undirected graphs with constant congestion"

Connected through hyperedge HE-6 (induced by source paper "linear kernels and single exponential algorithms via protrusion decompositions"):
  with members:
    - "slightly superexponential parameterized problems"
    - "bidimensionality and kernels"
    - "myhill nerode methods for hypergraphs"
    - "hitting and harvesting pumpkins"
    - "linear recognition of almost interval graphs"
    - "kernelization using structural parameters on sparse graph classes"
    - "meta kernelization with structural parameters"
    - "interval deletion is fixed parameter tractable"

Connected through hyperedge HE-7 (induced by source paper "on the parameterized intractability of monadic second order logic"):
  with members:
    - "lower bounds for the complexity of monadic second order logic"
    - "algorithmic meta theorems"
    - "deciding first order properties of locally tree decomposable structures"
    - "fixed parameter tractability definability and model checking"

Connected through hyperedge HE-8 (induced by source paper "lower bounds on the complexity of mso1 model checking"):
  with members:
    - "complexity of inference in graphical models"
    - "lower bounds for the complexity of monadic second order logic"
    - "are there any good digraph width measures"

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)