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: "truthful mechanisms for combinatorial ac electric power allocation"
  Abstract: Traditional studies of combinatorial auctions often only consider linear constraints (by which the demands for certain goods are limited by the corresponding supplies). The rise of smart grid presents a new class of auctions, characterized by quadratic constraints. Yu and Chau [AAMAS 13'] introduced the complex-demand knapsack problem, in which the demands are complex-valued and the capacity of supplies is described by the magnitude of total complex-valued demand. This naturally captures the power constraints in AC electric systems. In this paper, we provide a more complete study and generalize the problem to the multi-minded version, beyond the previously known 1/2-approximation algorithm for only a subclass of the problem. More precisely, we give a truthful PTAS for the case phi in [0,pi/2-delta], and a truthful FPTAS, which fully optimizes the objective function but violates the capacity constraint by at most (1+epsilon), for the case phi in (pi/2,pi-delta], where phi is the maximum angle between any two complex-valued demands and epsilon,delta>0 are arbitrarily small constants.

Connected through hyperedge HE-1 (induced by source paper "complex demand scheduling problem with application in smart grid"):
  with members:
    - "combinatorial optimization of ac optimal power flow with discrete demands in radial networks"
    - "optimal power flow with inelastic demands for demand response in radial distribution networks"
    - "truthful mechanisms for combinatorial allocation of electric power in alternating current electric systems for smart grid"
    - "online algorithm for demand response with inelastic demands and apparent power constraint"
    - "complex demand knapsack problems and incentives in ac power systems"
    - "a mazing 2 eps approximation for unsplittable flow on a path"
    - "vector bin packing with multiple choice"

Connected through hyperedge HE-2 (induced by source paper "optimal power flow with inelastic demands for demand response in radial distribution networks"):
  with members:
    - "truthful mechanisms for combinatorial allocation of electric power in alternating current electric systems for smart grid"
    - "ac feasibility on tree networks is np hard"
    - "complex demand knapsack problems and incentives in ac power systems"

Connected through hyperedge HE-3 (induced by source paper "online algorithm for demand response with inelastic demands and apparent power constraint"):
  with members:
    - "optimal power flow with inelastic demands for demand response in radial distribution networks"
    - "truthful mechanisms for combinatorial allocation of electric power in alternating current electric systems for smart grid"
    - "cost minimizing online algorithms for energy storage management with worst case guarantee"
    - "online algorithms for information aggregation from distributed and correlated sources"
    - "complex demand knapsack problems and incentives in ac power systems"
    - "online energy generation scheduling for microgrids with intermittent energy sources and co generation"

Connected through hyperedge HE-4 (induced by source paper "truthful mechanisms for combinatorial allocation of electric power in alternating current electric systems for smart grid"):
  with members:
    - "complex demand scheduling problem with application in smart grid"
    - "optimal power flow with inelastic demands for demand response in radial distribution networks"
    - "complex demand knapsack problems and incentives in ac power systems"
    - "mechanisms for multi unit auctions"
    - "computationally feasible vcg mechanisms"

Connected through hyperedge HE-5 (induced by source paper "approximation schemes for binary quadratic programming problems with low cp rank decompositions"):
  with members:
    - "complex demand knapsack problems and incentives in ac power systems"
    - "computing a nonnegative matrix factorization provably"
    - "submodular functions extensions distributions and algorithms a survey"
    - "on the complexity of nonnegative matrix factorization"

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.GT(Computer Science and Game Theory)