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: "improved pseudo polynomial time approximation for strip packing"
  Abstract: We study the strip packing problem, a classical packing problem which generalizes both bin packing and makespan minimization. Here we are given a set of axis-parallel rectangles in the two-dimensional plane and the goal is to pack them in a vertical strip of a fixed width such that the height of the obtained packing is minimized. The packing must be non-overlapping and the rectangles cannot be rotated. A reduction from the partition problem shows that no approximation better than 3/2 is possible for strip packing in polynomial time (assuming P$\neq$NP). Nadiradze and Wiese [SODA16] overcame this barrier by presenting a $(\frac{7}{5}+\epsilon)$-approximation algorithm in pseudo-polynomial-time (PPT). As the problem is strongly NP-hard, it does not admit an exact PPT algorithm. In this paper, we make further progress on the PPT approximability of strip packing, by presenting a $(\frac43+\epsilon)$-approximation algorithm. Our result is based on a non-trivial repacking of some rectangles in the \emph{empty space} left by the construction by Nadiradze and Wiese, and in some sense pushes their approach to its limit. Our PPT algorithm can be adapted to the case where we are allowed to rotate the rectangles by $90^\circ$, achieving the same approximation factor and breaking the polynomial-time approximation barrier of 3/2 for the case with rotations as well.

Connected through hyperedge HE-1 (induced by source paper "closing the gap for pseudo polynomial strip packing"):
  with members:
    - "scheduling monotone moldable jobs in linear time"
    - "complexity and inapproximability results for parallel task scheduling and strip packing"
    - "hardness of approximation for strip packing"
    - "improved approximation for two dimensional strip packing with polynomial bounded width"
    - "power strip packing of malleable demands in smart grid"

Connected through hyperedge HE-2 (induced by source paper "complexity and inapproximability results for parallel task scheduling and strip packing"):
  with members:
    - "scheduling monotone moldable jobs in linear time"
    - "closing the gap for pseudo polynomial strip packing"
    - "hardness of approximation for strip packing"
    - "improved approximation for two dimensional strip packing with polynomial bounded width"

Connected through hyperedge HE-3 (induced by source paper "approximating geometric knapsack via l packings"):
  with members:
    - "hardness of approximation for strip packing"
    - "improved approximation for two dimensional strip packing with polynomial bounded width"
    - "approximation schemes for maximum weight independent set of rectangles"

Connected through hyperedge HE-4 (induced by source paper "improved approximation for two dimensional strip packing with polynomial bounded width"):
  with members:
    - "complexity and inapproximability results for parallel task scheduling and strip packing"
    - "closing the gap for pseudo polynomial strip packing"
    - "hardness of approximation for strip packing"

Connected through hyperedge HE-5 (induced by source paper "hardness of approximation for strip packing"):
  with members:
    - "improved approximation for two dimensional strip packing with polynomial bounded width"
    - "approximation schemes for maximum weight independent set of rectangles"

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.DS(Data Structures and Algorithms)