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 intersection of all critical sets of a unicyclic graph"
  Abstract: A set S is independent in a graph G if no two vertices from S are adjacent. The independence number alpha(G) is the cardinality of a maximum independent set, while mu(G) is the size of a maximum matching in G. If alpha(G)+mu(G)=|V|, then G=(V,E) is called a Konig-Egervary graph. The number d_{c}(G)=max{|A|-|N(A)|} is called the critical difference of G (Zhang, 1990). By core(G) (corona(G)) we denote the intersection (union, respectively) of all maximum independent sets, while by ker(G) we mean the intersection of all critical independent sets. A connected graph having only one cycle is called unicyclic. It is known that ker(G) is a subset of core(G) for every graph G, while the equality is true for bipartite graphs (Levit and Mandrescu, 2011). For Konig-Egervary unicyclic graphs, the difference |core(G)|-|ker(G)| may equal any non-negative integer. In this paper we prove that if G is a non-Konig-Egervary unicyclic graph, then: (i) ker(G)= core(G) and (ii) |corona(G)|+|core(G)|=2*alpha(G)+1. Pay attention that |corona(G)|+|core(G)|=2*alpha(G) holds for every Konig-Egervary graph.

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"
    - "vertices belonging to all critical independent sets of a graph"
    - "on the structure of the minimum critical independent set 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"
    - "vertices belonging to all critical independent sets of a 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 "computing unique maximum matchings in o m time for konig egervary graphs and unicyclic graphs"):
  with members:
    - "on the core of a unicyclic graph"
    - "very well covered graphs of girth at least four and local maximum stable set greedoids"

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)