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: "approximation algorithms for polynomial expansion and low density graphs"
  Abstract: We study the family of intersection graphs of low density objects in low dimensional Euclidean space. This family is quite general, and includes planar graphs. We prove that such graphs have small separators. Next, we present efficient $(1+\varepsilon)$-approximation algorithms for these graphs, for Independent Set, Set Cover, and Dominating Set problems, among others. We also prove corresponding hardness of approximation for some of these optimization problems, providing a characterization of their intractability in terms of density.

Connected through hyperedge HE-1 (induced by source paper "diameter computation on h minor free graphs and graphs of bounded distance vc dimension"):
  with members:
    - "planar diameter via metric compression"
    - "fast diameter computation within split graphs"
    - "solving linear programs in the current matrix multiplication time"
    - "towards tight approximation bounds for graph diameter and eccentricities"
    - "multivariate analysis of orthogonal range searching and graph distances parameterized by treewidth"
    - "fully polynomial fpt algorithms for some classes of bounded clique width graphs"
    - "voronoi diagrams on planar graphs and computing the diameter in deterministic tilde o n 5 3 time"
    - "subquadratic algorithms for the diameter and the sum of pairwise distances in planar graphs"

Connected through hyperedge HE-2 (induced by source paper "fast counting with tensor networks"):
  with members:
    - "solving and sampling with many solutions satisfiability and other hard problems"
    - "tensor networks for dimensionality reduction and large scale optimization part 2 applications and future perspectives"
    - "implementing efficient all solutions sat solvers"
    - "tensor networks for dimensionality reduction and large scale optimization part 1 low rank tensor decompositions"
    - "aslib a benchmark library for algorithm selection"
    - "recent advances in graph partitioning"
    - "satzilla portfolio based algorithm selection for sat"
    - "a knowledge compilation map"

Connected through hyperedge HE-3 (induced by source paper "baker game and polynomial time approximation schemes"):
  with members:
    - "thin graph classes and polynomial time approximation schemes"
    - "simple ptas s for families of graphs excluding a minor"
    - "deciding first order properties of nowhere dense graphs"
    - "bidimensionality and eptas"

Connected through hyperedge HE-4 (induced by source paper "maximum matchings in geometric intersection graphs"):
  with members:
    - "triangles and girth in disk graphs and transmission graphs"
    - "dynamic planar voronoi diagrams for general distance functions and their algorithmic applications"
    - "a simplication of the mv matching algorithm and its proof"
    - "navigating central path with electrical flows from flows to matchings and back"

Connected through hyperedge HE-5 (induced by source paper "local search is a ptas for feedback vertex set in minor free graphs"):
  with members:
    - "local search yields approximation schemes for k means and k median in euclidean and minor free metrics"
    - "simple ptas s for families of graphs excluding a minor"
    - "solving the undirected feedback vertex set problem by local search"
    - "approximation algorithms for maximum independent set of pseudo disks"
    - "separator theorems for minor free and shallow minor free graphs with applications"
    - "bidimensionality and eptas"
    - "eigenvalue bounds spectral partitioning and metrical deformations via flows"

Connected through hyperedge HE-6 (induced by source paper "a framework for eth tight algorithms and lower bounds in geometric intersection graphs"):
  with members:
    - "the dominating set problem in geometric intersection graphs"
    - "finding hitting and packing cycles in subexponential time on unit disk graphs"
    - "the limited blessing of low dimensionality when 1 1 d is the best possible exponent for d dimensional geometric problems"
    - "optimal parameterized algorithms for planar facility location problems using voronoi diagrams"
    - "bidimensionality and geometric graphs"

Connected through hyperedge HE-7 (induced by source paper "greedy domination on biclique free graphs"):
  with members:
    - "analytical approach to parallel repetition"
    - "parameterized complexity of directed steiner tree on sparse graphs"

Connected through hyperedge HE-8 (induced by source paper "on pseudo disk hypergraphs"):
  with members:
    - "analytical approach to parallel repetition"

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.CG(Computational Geometry)