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: "counting homomorphisms to square free graphs modulo 2"
  Abstract: We study the problem HomsTo$H$ of counting, modulo 2, the homomorphisms from an input graph to a fixed undirected graph $H$. A characteristic feature of modular counting is that cancellations make wider classes of instances tractable than is the case for exact (non-modular) counting, so subtle dichotomy theorems can arise. We show the following dichotomy: for any $H$ that contains no 4-cycles, HomsTo$H$ is either in polynomial time or is $\oplus P$-complete. This confirms a conjecture of Faben and Jerrum that was previously only known to hold for trees and for a restricted class of treewidth-2 graphs called cactus graphs. We confirm the conjecture for a rich class of graphs including graphs of unbounded treewidth. In particular, we focus on square-free graphs, which are graphs without 4-cycles. These graphs arise frequently in combinatorics, for example in connection with the strong perfect graph theorem and in certain graph algorithms. Previous dichotomy theorems required the graph to be tree-like so that tree-like decompositions could be exploited in the proof. We prove the conjecture for a much richer class of graphs by adopting a much more general approach.

Connected through hyperedge HE-1 (induced by source paper "counting homomorphisms modulo a prime number"):
  with members:
    - "counting homomorphisms to trees modulo a prime"
    - "inapproximability of the independent set polynomial in the complex plane"
    - "the complexity of counting homomorphisms to cactus graphs modulo 2"
    - "the complexity of parity graph homomorphism an initial investigation"
    - "graph homomorphisms with complex values a dichotomy theorem"
    - "a complexity dichotomy for partition functions with mixed signs"

Connected through hyperedge HE-2 (induced by source paper "the complexity of approximately counting retractions to square free graphs"):
  with members:
    - "counting homomorphisms modulo a prime number"
    - "a dichotomy theorem for nonuniform csps"
    - "the complexity of approximately counting tree homomorphisms"
    - "the complexity of surjective homomorphism problems a survey"

Connected through hyperedge HE-3 (induced by source paper "counting homomorphisms to trees modulo a prime"):
  with members:
    - "the complexity of parity graph homomorphism an initial investigation"
    - "the complexity of counting solutions to generalised satisfiability problems modulo k"
    - "a complexity dichotomy for partition functions with mixed signs"

Connected through hyperedge HE-4 (induced by source paper "the complexity of counting surjective homomorphisms and compactions"):
  with members:
    - "homomorphisms are a good basis for counting small subgraphs"
    - "surjective h colouring new hardness results"
    - "homomorphisms are indeed a good basis for counting three fixed template dichotomy theorems for the price of one"
    - "note on the complexity of counting surjective homomorphisms and compactions"
    - "finding vertex surjective graph homomorphisms"
    - "the complexity of surjective homomorphism problems a survey"

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)