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: "some upper and lower bounds on psd rank"
  Abstract: Positive semidefinite rank (PSD-rank) is a relatively new quantity with applications to combinatorial optimization and communication complexity. We first study several basic properties of PSD-rank, and then develop new techniques for showing lower bounds on the PSD-rank. All of these bounds are based on viewing a positive semidefinite factorization of a matrix $M$ as a quantum communication protocol. These lower bounds depend on the entries of the matrix and not only on its support (the zero/nonzero pattern), overcoming a limitation of some previous techniques. We compare these new lower bounds with known bounds, and give examples where the new ones are better. As an application we determine the PSD-rank of (approximations of) some common matrices.

Connected through hyperedge HE-1 (induced by source paper "on modeling hard combinatorial optimization problems as linear programs refutations of the unconditional impossibility claims"):
  with members:
    - "on the existence of 0 1 polytopes with high semidefinite extension complexity"
    - "approximation limits of linear programs beyond hierarchies"
    - "how to solve ksat in polynomial time"
    - "the traveling salesman problem a linear programming formulation of"

Connected through hyperedge HE-2 (induced by source paper "exploring the bounds on the positive semidefinite rank"):
  with members:
    - "lower bounds on the size of semidefinite programming relaxations"
    - "the matching polytope has exponential extension complexity"

Connected through hyperedge HE-3 (induced by source paper "recommender systems inspired by the structure of quantum theory"):
  with members:
    - "expressive recommender systems through normalized nonnegative models"
    - "top n recommendations from expressive recommender systems"
    - "probabilistic latent semantic analysis"
    - "concepts and their dynamics a quantum theoretic modeling of human thought"
    - "bpr bayesian personalized ranking from implicit feedback"
    - "multi label prediction via compressed sensing"

Connected through hyperedge HE-4 (induced by source paper "top n recommendations from expressive recommender systems"):
  with members:
    - "expressive recommender systems through normalized nonnegative models"
    - "probabilistic latent semantic analysis"
    - "on the complexity of nonnegative matrix factorization"

Connected through hyperedge HE-5 (induced by source paper "the square root rank of the correlation polytope is exponential"):
  with members:
    - "lower bounds on the size of semidefinite programming relaxations"
    - "the matching polytope has exponential extension complexity"

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.CC(Computational Complexity)