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: "hierarchical self assembly of fractals with signal passing tiles extended abstract"
  Abstract: In this extended abstract, we present high-level overviews of tile-based self-assembling systems capable of producing complex, infinite, aperiodic structures known as discrete self-similar fractals. Fractals have a variety of interesting mathematical and structural properties, and by utilizing the bottom-up growth paradigm of self-assembly to create them we not only learn important techniques for building such complex structures, we also gain insight into how similar structural complexity arises in natural self-assembling systems. Our results fundamentally leverage hierarchical assembly processes, and use as our building blocks square "tile" components which are capable of activating and deactivating their binding "glues" a constant number of times each, based only on local interactions. We provide the first constructions capable of building arbitrary discrete self-similar fractals at scale factor 1, and many at temperature 1 (i.e. "non-cooperatively"), including the Sierpinski triangle.

Connected through hyperedge HE-1 (induced by source paper "hierarchical growth is necessary and sometimes sufficient to self assemble discrete self similar fractals"):
  with members:
    - "self assembly of 4 sided fractals in the two handed tile assembly model"
    - "hierarchical self assembly of fractals with signal passing tiles"
    - "scaled tree fractals do not strictly self assemble"
    - "strict self assembly of fractals using multiple hands"
    - "parallelism and time in hierarchical self assembly"
    - "approximate self assembly of the sierpinski triangle"
    - "strict self assembly of discrete sierpinski triangles"
    - "self assembly of the discrete sierpinski carpet and related fractals"

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"
    - "universal simulation of directed systems in the abstract tile assembly model requires undirectedness"
    - "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"

Connected through hyperedge HE-3 (induced by source paper "hierarchical self assembly of fractals with signal passing tiles"):
  with members:
    - "self assembly of 4 sided fractals in the two handed tile assembly model"
    - "replication of arbitrary hole free shapes via self assembly with signal passing tiles extended abstract"
    - "scaled tree fractals do not strictly self assemble"
    - "strict self assembly of fractals using multiple hands"
    - "signal transmission across tile assemblies 3d static tiles simulate active self assembly by 2d signal passing tiles"
    - "asynchronous signal passing for tile self assembly fuel efficient computation and efficient assembly of shapes"
    - "two hands are better than one up to constant factors"
    - "approximate self assembly of the sierpinski triangle"

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.ET(Emerging Technologies)