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: "emptyheaded boolean algebra based graph processing"
  Abstract: We present a graph pattern engine, EmptyHeaded, that uses recent algorithmic advances in join processing to compile patterns into Boolean algebra operations that exploit SIMD parallelism. The EmptyHeaded engine demonstrates that treating graph patterns as a general join processing problem can compete with and often outperform both specialized approaches and existing OLAP systems on graph queries. The core Boolean algebra operation performed in EmptyHeaded is set intersection. Extracting SIMD parallelism during set intersections on graph data is challenging because graph data can be skewed in several dierent ways. Our contributions are a demonstration of this new type of engine with Boolean algebra at its core, an exploration of set intersection representations and algorithms for set intersections that are optimized for skew. We demonstrate that EmptyHeaded outperforms specialized graph engines by over an order of magnitude and relational systems by over two orders of magnitude. Our results suggest that this new style of engine is a promising new direction for future graph engines and accelerators.

Connected through hyperedge HE-1 (induced by source paper "survey and taxonomy of lossless graph compression and space efficient graph representations"):
  with members:
    - "grammar based graph compression"
    - "compressing networks with super nodes"
    - "graphzip dictionary based compression for mining graph streams"
    - "parallel construction of compact planar embeddings"
    - "compressed representation of dynamic binary relations with applications"
    - "a succinct data structure for self indexing ternary relations"
    - "fully dynamic de bruijn graphs"
    - "compressing graphs and indexes with recursive graph bisection"

Connected through hyperedge HE-2 (induced by source paper "gunrock gpu graph analytics"):
  with members:
    - "a comparative study on exact triangle counting algorithms on the gpu"
    - "snap a general purpose network analysis and graph mining library"
    - "counting triangles in large graphs on gpu"
    - "mathematical foundations of the graphblas"
    - "accelerating direction optimized breadth first search on hybrid architectures"
    - "multi gpu graph analytics"
    - "gunrock a high performance graph processing library on the gpu"
    - "efficient large scale graph processing on hybrid cpu and gpu systems"

Connected through hyperedge HE-3 (induced by source paper "computing join queries with functional dependencies"):
  with members:
    - "size bounds and query plans for relational joins"
    - "constraint solving via fractional edge covers"
    - "entropy bounds for conjunctive queries with functional dependencies"
    - "it s all a matter of degree using degree information to optimize multiway joins"
    - "skew strikes back new developments in the theory of join algorithms"
    - "tractable hypergraph properties for constraint satisfaction and conjunctive queries"

Connected through hyperedge HE-4 (induced by source paper "flexible caching in trie joins"):
  with members:
    - "aggregations over generalized hypertree decompositions"
    - "join processing for graph patterns an old dog with new tricks"
    - "faq questions asked frequently"
    - "aggregation and ordering in factorised databases"
    - "skew strikes back new developments in the theory of join algorithms"
    - "hypertree decompositions and tractable queries"

Connected through hyperedge HE-5 (induced by source paper "faq questions asked frequently"):
  with members:
    - "size bounds and query plans for relational joins"
    - "constraint solving via fractional edge covers"
    - "what do shannon type inequalities submodular width and disjunctive datalog have to do with one another"
    - "computing join queries with functional dependencies"
    - "general and fractional hypertree decompositions hard and easy cases"
    - "join processing for graph patterns an old dog with new tricks"
    - "joins via geometric resolutions worst case and beyond"
    - "a trichotomy in the complexity of counting answers to conjunctive queries"

Connected through hyperedge HE-6 (induced by source paper "join processing for graph patterns an old dog with new tricks"):
  with members:
    - "size bounds and query plans for relational joins"
    - "constraint solving via fractional edge covers"
    - "transaction repair full serializability without locks"
    - "incremental maintenance for leapfrog triejoin"
    - "beyond worst case analysis for joins with minesweeper"
    - "skew strikes back new developments in the theory of join algorithms"
    - "optimal aggregation algorithms for middleware"

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.DB(Databases)