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: "boolean operations joins and the extended low hierarchy"
  Abstract: We prove that the join of two sets may actually fall into a lower level of the extended low hierarchy than either of the sets. In particular, there exist sets that are not in the second level of the extended low hierarchy, EL_2, yet their join is in EL_2. That is, in terms of extended lowness, the join operator can lower complexity. Since in a strong intuitive sense the join does not lower complexity, our result suggests that the extended low hierarchy is unnatural as a complexity measure. We also study the closure properties of EL_ and prove that EL_2 is not closed under certain Boolean operations. To this end, we establish the first known (and optimal) EL_2 lower bounds for certain notions generalizing Selman's P-selectivity, which may be regarded as an interesting result in its own right.

Connected through hyperedge HE-1 (induced by source paper "closure and nonclosure properties of the compressible and rankable sets"):
  with members:
    - "recursion theoretic ranking and compression"

Connected through hyperedge HE-2 (induced by source paper "hybrid elections broaden complexity theoretic resistance to control"):
  with members:
    - "sincere strategy preference based approval voting fully resists constructive control and broadly resists destructive control"
    - "llull and copeland voting computationally resist bribery and control"
    - "copeland voting fully resists constructive control"
    - "a richer understanding of the complexity of election systems"
    - "anyone but him the complexity of precluding an alternative"
    - "guarantees for the success frequency of an algorithm for finding dodgson election winners"
    - "universal voting protocol tweaks to make manipulation hard"
    - "how many candidates are needed to make elections hard to manipulate"

Connected through hyperedge HE-3 (induced by source paper "tally np sets and easy census functions"):
  with members:
    - "a downward collapse within the polynomial hierarchy"
    - "unambiguous computation boolean hierarchies and sparse turing complete sets"

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.CC(Computational Complexity)