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: "approximating minimum cost edge covers of crossing biset families"
  Abstract: An ordered pair $\hat{S}=(S,S^+)$ of subsets of $V$ is called a {\em biset} if $S \subseteq S^+$; $(V-S^+,V-S)$ is the co-biset of $\hat{S}$. Two bisets $\hat{X},\hat{Y}$ intersect if $X \cap Y \neq \emptyset$ and cross if both $X \cap Y \neq \emptyset$ and $X^+ \cup Y^+ \neq V$. The intersection and the union of two bisets $\hat{X},\hat{Y}$ is defined by $\hat{X} \cap \hat{Y} = (X \cap Y, X^+ \cap Y^+)$ and $\hat{X} \cup \hat{Y} = (X \cup Y,X^+ \cup Y^+)$. A biset-family ${\cal F}$ is crossing (intersecting) if $\hat{X} \cap \hat{Y}, \hat{X} \cup \hat{Y} \in {\cal F}$ for any $\hat{X},\hat{Y} \in {\cal F}$ that cross (intersect). A directed edge covers a biset $\hat{S}$ if it goes from $S$ to $V-S^+$. We consider the problem of covering a crossing biset-family ${\cal F}$ by a minimum-cost set of directed edges. While for intersecting ${\cal F}$, a standard primal-dual algorithm computes an optimal solution, the approximability of the case of crossing ${\cal F}$ is not yet understood, as it includes several NP-hard problems, for which a poly-logarithmic approximation was discovered only recently. Let us say that a biset-family ${\cal F}$ is $k$-regular if $\hat{X} \cap \hat{Y}, \hat{X} \cup \hat{Y} \in {\cal F}$ for any $\hat{X},\hat{Y} \in {\cal F}$ with $|V-(X \cup Y)| \geq k+1$ that intersect. In this paper we obtain an $O(\log |V|)$-approximation algorithm for arbitrary crossing ${\cal F}$; if in addition both ${\cal F}$ and the family of co-bisets of ${\cal F}$ are $k$-regular, our ratios are: $O(\log \frac{|V|}{|V|-k})$ if $|S^+ \setminus S|=k$ for all $\hat{S} \in {\cal F}$, and $O(\frac{|V|}{|V|-k} \log \frac{|V|}{|V|-k})$ if $|S^+ \setminus S| \leq k$ for all $\hat{S} \in {\cal F}$. Using these generic algorithms, we derive approximation algorithms for some network design problems.

Connected through hyperedge HE-1 (induced by source paper "a 4 epsilon approximation for k connected subgraphs"):
  with members:
    - "iterative rounding approximation algorithms for degree bounded node connectivity network design"
    - "approximating minimum cost k node connected subgraphs via independence free graphs"

Connected through hyperedge HE-2 (induced by source paper "iterative rounding approximation algorithms for degree bounded node connectivity network design"):
  with members:
    - "approximating minimum cost k node connected subgraphs via independence free graphs"
    - "approximating subset k connectivity problems"
    - "on generalizations of network design problems with degree bounds"
    - "improved algorithm for degree bounded survivable network design problem"
    - "an o k 3 log n approximation algorithm for vertex connectivity survivable network design"

Connected through hyperedge HE-3 (induced by source paper "approximating minimum cost k node connected subgraphs via independence free graphs"):
  with members:
    - "an o k 3 log n approximation algorithm for vertex connectivity survivable network design"
    - "approximate graph coloring by semidefinite programming"

Connected through hyperedge HE-4 (induced by source paper "an improved approximation algorithm for the minimum cost subset k connected subgraph problem"):
  with members:
    - "parameters of two prover one round game and the hardness of connectivity problems"
    - "approximating subset k connectivity problems"
    - "an o k 3 log n approximation algorithm for vertex connectivity survivable network design"

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.DS(Data Structures and Algorithms)