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: "on the structure of the minimum critical independent set of a graph"
  Abstract: Let G=(V,E). A set S is independent if no two vertices from S are adjacent. The number d(X)= |X|-|N(X)| is the difference of X, and an independent set A is critical if d(A) = max{d(I):I is an independent set}. Let us recall that ker(G) is the intersection of all critical independent sets, and core(G) is the intersection of all maximum independent sets. Recently, it was established that ker(G) is a subset of core(G) is true for every graph, while the corresponding equality holds for bipartite graphs. In this paper we present various structural properties of ker(G). The main finding claims that ker(G) is equal to the union of all inclusion minimal independent sets with positive difference.

Connected through hyperedge HE-1 (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"
    - "vertices belonging to all critical independent sets of a graph"
    - "critical sets in bipartite graphs"

Connected through hyperedge HE-2 (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"
    - "vertices belonging to all critical independent sets of a graph"
    - "critical sets in bipartite graphs"

Connected through hyperedge HE-3 (induced by source paper "critical independent sets of a graph"):
  with members:
    - "a set and collection lemma"
    - "vertices belonging to all critical independent sets of a graph"
    - "critical sets in bipartite graphs"

Connected through hyperedge HE-4 (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"
    - "vertices belonging to all critical independent sets of a graph"
    - "critical sets in bipartite 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)