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: "partial star products a local covering approach for the recognition of approximate cartesian product graphs"
  Abstract: This paper is concerned with the recognition of approximate graph products with respect to the Cartesian product. Most graphs are prime, although they can have a rich product-like structure. The proposed algorithms are based on a local approach that covers a graph by small subgraphs, so-called partial star products, and then utilizes this information to derive the global factors and an embedding of the graph under investigation into Cartesian product graphs.

Connected through hyperedge HE-1 (induced by source paper "on the cartesian skeleton and the factorization of the strong product of digraphs"):
  with members:
    - "local algorithms for the prime factorization of strong product graphs"
    - "strong products of hypergraphs unique prime factorization theorems and algorithms"
    - "fast recognition of partial star products and quasi cartesian products"
    - "a survey on hypergraph products"

Connected through hyperedge HE-2 (induced by source paper "on tree representations of relations and graphs symbolic ultrametrics and cograph edge decompositions"):
  with members:
    - "from event labeled gene trees to species trees"
    - "phylogenomics with paralogs"
    - "on symbolic ultrametrics cotree representations and cograph edge decompositions and partitions"

Connected through hyperedge HE-3 (induced by source paper "the relaxed square property"):
  with members:
    - "unique square property equitable partitions and product like graphs"
    - "fast recognition of partial star products and quasi cartesian products"

Connected through hyperedge HE-4 (induced by source paper "unique square property equitable partitions and product like graphs"):
  with members:
    - "local algorithms for the prime factorization of strong product graphs"

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)