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: "the price of connectivity for vertex cover"
  Abstract: The vertex cover number of a graph is the minimum number of vertices that are needed to cover all edges. When those vertices are further required to induce a connected subgraph, the corresponding number is called the connected vertex cover number, and is always greater or equal to the vertex cover number. #R##N#Connected vertex covers are found in many applications, and the relationship between those two graph invariants is therefore a natural question to investigate. For that purpose, we introduce the {\em Price of Connectivity}, defined as the ratio between the two vertex cover numbers. We prove that the price of connectivity is at most 2 for arbitrary graphs. We further consider graph classes in which the price of connectivity of every induced subgraph is bounded by some real number $t$. We obtain forbidden induced subgraph characterizations for every real value $t \leq 3/2$. #R##N#We also investigate critical graphs for this property, namely, graphs whose price of connectivity is strictly greater than that of any proper induced subgraph. Those are the only graphs that can appear in a forbidden subgraph characterization for the hereditary property of having a price of connectivity at most $t$. In particular, we completely characterize the critical graphs that are also chordal. #R##N#Finally, we also consider the question of computing the price of connectivity of a given graph. Unsurprisingly, the decision version of this question is NP-hard. In fact, we show that it is even complete for the class $\Theta_2^P = P^{NP[\log]}$, the class of decision problems that can be solved in polynomial time, provided we can make $O(\log n)$ queries to an NP-oracle. This paves the way for a thorough investigation of the complexity of problems involving ratios of graph invariants.

Connected through hyperedge HE-1 (induced by source paper "on cycle transversals and their connected variants in the absence of a small linear forest"):
  with members:
    - "subexponential algorithms for variants of homomorphism problem in string graphs"
    - "connected vertex cover for sp_1 p_5 free graphs"
    - "minimum connected transversals in graphs new hardness results and tractable cases using the price of connectivity"
    - "polynomial time algorithm for maximum weight independent set on p_6 free graphs"
    - "independent feedback vertex set for p_5 free graphs"

Connected through hyperedge HE-2 (induced by source paper "connected vertex cover for sp_1 p_5 free graphs"):
  with members:
    - "contracting to a longest path in h free graphs"
    - "minimum connected transversals in graphs new hardness results and tractable cases using the price of connectivity"
    - "polynomial time algorithm for maximum weight independent set on p_6 free graphs"
    - "independent feedback vertex set for p_5 free graphs"
    - "contracting bipartite graphs to paths and cycles"
    - "maximum weight independent set in lclaw free graphs in polynomial time"

Connected through hyperedge HE-3 (induced by source paper "minimum connected transversals in graphs new hardness results and tractable cases using the price of connectivity"):
  with members:
    - "independent feedback vertex set for p_5 free graphs"
    - "enumeration and maximum number of minimal connected vertex covers in graphs"
    - "solving connectivity problems parameterized by treewidth in single exponential time"
    - "fpt algorithms for connected feedback vertex set"

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)