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: "structural tractability of counting of solutions to conjunctive queries"
  Abstract: In this paper we explore the problem of counting solutions to conjunctive queries. We consider a parameter called the \emph{quantified star size} of a formula $\varphi$ which measures how the free variables are spread in $\varphi$. We show that for conjunctive queries that admit nice decomposition properties (such as being of bounded treewidth or generalized hypertree width) bounded quantified star size exactly characterizes the classes of queries for which counting the number of solutions is tractable. This also allows us to fully characterize the conjunctive queries for which counting the solutions is tractable in the case of bounded arity. To illustrate the applicability of our results, we also show that computing the quantified star size of a formula is possible in time $n^{O(k)}$ for queries of generalized hypertree width $k$. Furthermore, quantified star size is even fixed parameter tractable parameterized by some other width measures, while it is $\W{1}$-hard for generalized hypertree width and thus unlikely to be fixed parameter tractable. We finally show how to compute an approximation of quantified star size in polynomial time where the approximation ratio depends on the width of the input.

Connected through hyperedge HE-1 (induced by source paper "counting answers to existential questions"):
  with members:
    - "homomorphisms are a good basis for counting small subgraphs"
    - "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"
    - "counting answers to existential positive queries a complexity classification"
    - "complexity of counting subgraphs only the boundedness of the vertex cover number counts"
    - "a trichotomy in the complexity of counting answers to conjunctive queries"
    - "polynomial bounds for the grid minor theorem"
    - "fixed parameter tractability definability and model checking"

Connected through hyperedge HE-2 (induced by source paper "dependency weighted aggregation on factorized databases"):
  with members:
    - "constraint solving via fractional edge covers"
    - "hypergraph acyclicity and propositional model counting"
    - "gym a multiround join algorithm in mapreduce"
    - "hypertree decompositions and tractable queries"
    - "a knowledge compilation map"

Connected through hyperedge HE-3 (induced by source paper "juggling functions inside a database"):
  with members:
    - "size bounds and query plans for relational joins"
    - "constraint solving via fractional edge covers"
    - "in database learning with sparse tensors"
    - "what do shannon type inequalities submodular width and disjunctive datalog have to do with one another"
    - "computing join queries with functional dependencies"
    - "flexible caching in trie joins"
    - "join processing for graph patterns an old dog with new tricks"
    - "faq questions asked frequently"

Connected through hyperedge HE-4 (induced by source paper "answering conjunctive queries under updates"):
  with members:
    - "answering fo mod queries under updates on bounded degree databases"
    - "size bounds and query plans for relational joins"
    - "dynamic conjunctive queries"
    - "faster online matrix vector multiplication"
    - "unifying and strengthening hardness for dynamic problems via the online matrix vector multiplication conjecture"
    - "joins via geometric resolutions worst case and beyond"
    - "a trichotomy in the complexity of counting answers to conjunctive queries"
    - "beyond worst case analysis for joins with minesweeper"

Connected through hyperedge HE-5 (induced by source paper "compressed representations of conjunctive query results"):
  with members:
    - "size bounds and query plans for relational joins"
    - "conditional lower bounds for space time tradeoffs"
    - "answering conjunctive queries under updates"
    - "extracting and analyzing hidden graphs from relational databases"
    - "data structure lower bounds for document indexing problems"
    - "aggregation and ordering in factorised databases"
    - "skew strikes back new developments in the theory of join algorithms"
    - "fdb a query engine for factorised relational databases"

Connected through hyperedge HE-6 (induced by source paper "answering ucqs under updates and in the presence of integrity constraints"):
  with members:
    - "dynamic conjunctive queries"
    - "answering conjunctive queries under updates"
    - "computing join queries with functional dependencies"
    - "incremental view maintenance for collection programming"
    - "a trichotomy in the complexity of counting answers to conjunctive queries"
    - "tractable hypergraph properties for constraint satisfaction and conjunctive queries"

Connected through hyperedge HE-7 (induced by source paper "first order query evaluation with cardinality conditions"):
  with members:
    - "first order logic with counting at least weak hanf normal forms always exist and can be computed"
    - "deciding first order properties of nowhere dense graphs"
    - "algorithmic meta theorems"
    - "deciding first order properties of locally tree decomposable structures"

Connected through hyperedge HE-8 (induced by source paper "counting answers to existential positive queries a complexity classification"):
  with members:
    - "the tractability frontier of graph like first order query sets"
    - "a trichotomy in the complexity of counting answers to conjunctive queries"
    - "one hierarchy spawns another graph deconstructions and the complexity classification of conjunctive queries"
    - "on the complexity of existential positive queries"
    - "tractable hypergraph properties for constraint satisfaction and conjunctive queries"

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.LO(Logic in Computer Science)