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: "popular matchings with two sided preferences and one sided ties"
  Abstract: We are given a bipartite graph $G = (A \cup B, E)$ where each vertex has a preference list ranking its neighbors: in particular, every $a \in A$ ranks its neighbors in a strict order of preference, whereas the preference lists of $b \in B$ may contain ties. A matching $M$ is popular if there is no matching $M'$ such that the number of vertices that prefer $M'$ to $M$ exceeds the number of vertices that prefer $M$ to~$M'$. We show that the problem of deciding whether $G$ admits a popular matching or not is NP-hard. This is the case even when every $b \in B$ either has a strict preference list or puts all its neighbors into a single tie. In contrast, we show that the problem becomes polynomially solvable in the case when each $b \in B$ puts all its neighbors into a single tie. That is, all neighbors of $b$ are tied in $b$'s list and $b$ desires to be matched to any of them. Our main result is an $O(n^2)$ algorithm (where $n = |A \cup B|$) for the popular matching problem in this model. Note that this model is quite different from the model where vertices in $B$ have no preferences and do not care whether they are matched or not.

Connected through hyperedge HE-1 (induced by source paper "understanding popular matchings via stable matchings"):
  with members:
    - "max size popular matchings and extensions"
    - "popular matching in roommates setting is np hard"
    - "popular matchings and limits to tractability"
    - "popular edges and dominant matchings"

Connected through hyperedge HE-2 (induced by source paper "popular branchings and their dual certificates"):
  with members:
    - "the convergence of iterative delegations in liquid democracy in a social network"
    - "popular matching in roommates setting is np hard"
    - "popular matchings and limits to tractability"
    - "the fluid mechanics of liquid democracy"
    - "binary voting with delegable proxy an analysis of liquid democracy"
    - "popular edges and dominant matchings"

Connected through hyperedge HE-3 (induced by source paper "minimal envy and popular matchings"):
  with members:
    - "competitive division of a mixed manna"
    - "counting popular matchings in house allocation problems"
    - "weighted popular matchings"
    - "exact complexity of the winner problem for young elections"

Connected through hyperedge HE-4 (induced by source paper "popularity stability and the dominant matching polytope"):
  with members:
    - "max size popular matchings and extensions"
    - "popular matching in roommates setting is np hard"
    - "popular matchings and limits to tractability"
    - "popular edges and dominant matchings"

Connected through hyperedge HE-5 (induced by source paper "the popular roommates problem"):
  with members:
    - "max size popular matchings and extensions"
    - "popular matching in roommates setting is np hard"
    - "popular edges and dominant matchings"

Connected through hyperedge HE-6 (induced by source paper "max size popular matchings and extensions"):
  with members:
    - "popular matchings with multiple partners"
    - "popular edges and dominant matchings"

Connected through hyperedge HE-7 (induced by source paper "popular matchings with multiple partners"):
  with members:
    - "popularity in the generalized hospital residents setting"
    - "popular edges and dominant matchings"
    - "socially stable matchings in the hospitals residents problem"

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.DM(Discrete Mathematics)