human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "lift and project integrality gaps for the traveling salesperson problem"):
  Abstract: We study the lift-and-project procedures of Lov{\'a}sz-Schrijver and Sherali-Adams applied to the standard linear programming relaxation of the traveling salesperson problem with triangle inequality. For the asymmetric TSP tour problem, Charikar, Goemans, and Karloff (FOCS 2004) proved that the integrality gap of the standard relaxation is at least 2. We prove that after one round of the Lov{\'a}sz-Schrijver or Sherali-Adams procedures, the integrality gap of the asymmetric TSP tour problem is at least 3/2, with a small caveat on which version of the standard relaxation is used. For the symmetric TSP tour problem, the integrality gap of the standard relaxation is known to be at least 4/3, and Cheung (SIOPT 2005) proved that it remains at least 4/3 after $o(n)$ rounds of the Lov{\'a}sz-Schrijver procedure, where $n$ is the number of nodes. For the symmetric TSP path problem, the integrality gap of the standard relaxation is known to be at least 3/2, and we prove that it remains at least 3/2 after $o(n)$ rounds of the Lov{\'a}sz-Schrijver procedure, by a simple reduction to Cheung's result.

Includes members:
  Member "eight fifth approximation for the path tsp":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "constant factor approximation algorithms for parity constrained facility location problems")
  Member "shorter tours by nicer ears 7 5 approximation for graphic tsp 3 2 for the path version and 4 3 for two edge connected subgraphs":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "travelling on graphs with small highway dimension")
  Member "improved inapproximability for tsp":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "travelling on graphs with small highway dimension")
  Member "improving christofides algorithm for the s t path tsp":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "reducing path tsp to tsp")
  Member "approximating graphic tsp by matchings":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "simple cubic graphs with no short traveling salesman tour")
  Member "lp based approximation algorithms for traveling salesman path problems":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "an lp based 3 2 approximation algorithm for the graphic s t path tsp")
  Member "13 9 approximation for graphic tsp":
    also connected through other hyperedges:
      - Hyperedge HE-7 (induced by source paper "reducing path tsp to tsp")
  Member "asymmetric traveling salesman path and directed latency problems":
    also connected through other hyperedges:
      - Hyperedge HE-8 (induced by source paper "a constant factor approximation for directed latency in quasi polynomial time")

Question: Please tell me which class the source paper 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)