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: "vertices belonging to all critical independent sets of a graph"
  Abstract: Let G=(V,E) be a graph. A set S is independent if no two vertices from S are adjacent. The independence number alpha(G) is the cardinality of a maximum independent set, and mu(G) is the size of a maximum matching. The number id_{c}(G)=max{|I|-|N(I)|:I is an independent set} is called the critical independence difference of G, and A is critical if |A|-|N(A)|=id_{c}(G). We define core(G) as the intersection of all maximum independent sets, and ker(G)as the intersection of all critical independent sets. In this paper we prove that if a graph G is non-quasi-regularizable (i.e., there exists some independent set A, such that |A|>|N(A)|), then: ker(G) is a subset of core(G), and |ker(G)|> id_{c}(G) >= alpha(G)-mu(G) > 0.

Connected through hyperedge HE-1 (induced by source paper "on the critical difference of almost bipartite graphs"):
  with members:
    - "a set and collection lemma"
    - "on the core of a unicyclic graph"
    - "critical sets in bipartite graphs"
    - "a characterization of konig egervary graphs using a common property of all maximum matchings"

Connected through hyperedge HE-2 (induced by source paper "critical and maximum independent sets of a graph"):
  with members:
    - "on the power of simple reductions for the maximum independent set problem"
    - "a set and collection lemma"
    - "on the core of a unicyclic graph"
    - "on the intersection of all critical sets of a unicyclic graph"
    - "on the structure of the minimum critical independent set of a graph"
    - "critical sets in bipartite graphs"

Connected through hyperedge HE-3 (induced by source paper "monotonic properties of collections of maximum independent sets of a graph"):
  with members:
    - "a set and collection lemma"
    - "on the core of a unicyclic graph"
    - "on the intersection of all critical sets of a unicyclic graph"
    - "on the structure of the minimum critical independent set of a graph"
    - "critical sets in bipartite graphs"

Connected through hyperedge HE-4 (induced by source paper "on konig egervary collections of maximum critical independent sets"):
  with members:
    - "critical and maximum independent sets of a graph"
    - "monotonic properties of collections of maximum independent sets of a graph"
    - "critical independent sets of a graph"
    - "a set and collection lemma"

Connected through hyperedge HE-5 (induced by source paper "critical independent sets of a graph"):
  with members:
    - "a set and collection lemma"
    - "on the structure of the minimum critical independent set of a graph"
    - "critical sets in bipartite graphs"

Connected through hyperedge HE-6 (induced by source paper "on the intersection of all critical sets of a unicyclic graph"):
  with members:
    - "a set and collection lemma"
    - "on the core of a unicyclic graph"
    - "on the structure of the minimum critical independent set of a graph"
    - "critical sets in bipartite graphs"

Connected through hyperedge HE-7 (induced by source paper "on the structure of the minimum critical independent set of a graph"):
  with members:
    - "critical sets in bipartite graphs"

Connected through hyperedge HE-8 (induced by source paper "critical sets in bipartite graphs"):
  with members:
    - "a set and collection lemma"

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)