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: "universal simulation of directed systems in the abstract tile assembly model requires undirectedness"
  Abstract: As a mathematical model of self-assembling systems, Winfree's abstract Tile Assembly Model (aTAM) is a remarkable platform for studying the behaviors and powers of self-assembling systems. Capable of Turing universal computation, the aTAM allows algorithmic self-assembly, in which the components can be designed so that the rules governing their behaviors force them to inherently execute prescribed algorithms as they combine. Adding to its completeness, the aTAM was shown to also be intrinsically universal, which means that there exists a single tile set such that for any arbitrary input aTAM system, that tile set can be configured into a seed structure which will then cause self-assembly using that tile set to simulate the input system, capturing its full dynamics modulo only a scale factor. However, the universal simulator previously given makes use of nondeterminism in terms of tile types placed in several key locations when different assembly sequences are followed, even when simulating a directed system, meaning one that has exactly one unique terminal assembly. The question then became whether or not that nondeterminism is fundamentally required. Here, we answer that in the affirmative: the class of directed systems in the aTAM is not intrinsically universal, meaning there is no universal simulator for directed systems which itself is always directed. This provides insight into the role of nondeterminism in self-assembly, which is itself a fundamentally nondeterministic process. To achieve this result we leverage powerful results of computational complexity hierarchies, including tight bounds on both best and worst-case complexities of decidable languages, to design systems with precisely controllable space resources available to embedded computations. We also develop novel techniques for designing systems containing subsystems with disjoint, mutually exclusive computational powers.

Connected through hyperedge HE-1 (induced by source paper "the impacts of dimensionality diffusion and directedness on intrinsic universality in the abstract tile assembly model"):
  with members:
    - "self assembly of 3 d structures using 2 d folding tiles"
    - "the non cooperative tile assembly model is not intrinsically universal or capable of bounded turing machine simulation"
    - "the simulation powers and limitations of higher temperature hierarchical self assembly systems"
    - "computing in continuous space with self assembling polygonal tiles"
    - "doubles and negatives are positive in self assembly"
    - "the power of duples in self assembly it s not so hip to be square"
    - "signal transmission across tile assemblies 3d static tiles simulate active self assembly by 2d signal passing tiles"
    - "intrinsic universality in tile self assembly requires cooperation"

Connected through hyperedge HE-2 (induced by source paper "self assembly of 4 sided fractals in the two handed tile assembly model"):
  with members:
    - "hierarchical growth is necessary and sometimes sufficient to self assemble discrete self similar fractals"
    - "the non cooperative tile assembly model is not intrinsically universal or capable of bounded turing machine simulation"
    - "hierarchical self assembly of fractals with signal passing tiles extended abstract"
    - "hierarchical self assembly of fractals with signal passing tiles"
    - "self assembly of shapes at constant scale using repulsive forces"
    - "universal shape replicators via self assembly with attractive and repulsive forces"
    - "the simulation powers and limitations of higher temperature hierarchical self assembly systems"
    - "computing in continuous space with self assembling polygonal tiles"

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.CG(Computational Geometry)