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: "twenty five comparators is optimal when sorting nine inputs and twenty nine for ten"
  Abstract: This paper describes a computer-assisted non-existence proof of 9-input sorting networks consisting of 24 comparators, hence showing that the 25-comparator sorting network found by Floyd in 1964 is optimal. As a corollary, we obtain that the 29-comparator network found by Waksman in 1969 is optimal when sorting 10 inputs. This closes the two smallest open instances of the optimal-size sorting network problem, which have been open since the results of Floyd and Knuth from 1966 proving optimality for sorting networks of up to 8 inputs. The proof involves a combination of two methodologies: one based on exploiting the abundance of symmetries in sorting networks, and the other based on an encoding of the problem to that of satisfiability of propositional logic. We illustrate that, while each of these can single-handedly solve smaller instances of the problem, it is their combination that leads to the more efficient solution that scales to handle 9 inputs.

Connected through hyperedge HE-1 (induced by source paper "engineering faster sorters for small sets of elements"):
  with members:
    - "scalable string and suffix sorting algorithms techniques and tools"
    - "in place parallel super scalar samplesort ips 4 o"
    - "robust massively parallel sorting"
    - "parallel string sample sort"
    - "gpu sample sort"

Connected through hyperedge HE-2 (induced by source paper "design space exploration as quantified satisfaction"):
  with members:
    - "depqbf 6 0 a search based qbf solver beyond traditional qcdcl"
    - "practical graph isomorphism ii"
    - "anytime heuristic search"

Connected through hyperedge HE-3 (induced by source paper "optimal depth sorting networks"):
  with members:
    - "sorting networks to the end and back again"
    - "solving and verifying the boolean pythagorean triples problem via cube and conquer"
    - "new bounds on optimal sorting networks"
    - "computing the ramsey number r 4 3 3 using abstraction and symmetry breaking"
    - "applying sorting networks to synthesize optimized sorting libraries"
    - "sorting networks the end game"
    - "the quest for optimal sorting networks efficient generation of two layer prefixes"
    - "computer aided proof of erdos discrepancy properties"

Connected through hyperedge HE-4 (induced by source paper "an improved subsumption testing algorithm for the optimal size sorting network problem"):
  with members:
    - "sorting networks to the end and back again"
    - "new bounds on optimal sorting networks"
    - "the quest for optimal sorting networks efficient generation of two layer prefixes"
    - "optimal sorting networks"

Connected through hyperedge HE-5 (induced by source paper "optimizing a certified proof checker for a large scale computer generated proof"):
  with members:
    - "formalizing size optimal sorting networks extracting a certified proof checker"
    - "the certification problem format"
    - "efficient generation of correctness certificates for the abstract domain of polyhedra"
    - "computer certified efficient exact reals in coq"
    - "certified exact transcendental real number computation in coq"

Connected through hyperedge HE-6 (induced by source paper "applying sorting networks to synthesize optimized sorting libraries"):
  with members:
    - "new bounds on optimal sorting networks"
    - "sorting networks the end game"
    - "the quest for optimal sorting networks efficient generation of two layer prefixes"
    - "optimal sorting networks"

Connected through hyperedge HE-7 (induced by source paper "sorting networks the end game"):
  with members:
    - "the quest for optimal sorting networks efficient generation of two layer prefixes"
    - "faster sorting networks for 17 19 and 20 inputs"
    - "optimal sorting networks"

Connected through hyperedge HE-8 (induced by source paper "formalizing size optimal sorting networks extracting a certified proof checker"):
  with members:
    - "optimizing a certified proof checker for a large scale computer generated proof"
    - "the certification problem format"
    - "efficient generation of correctness certificates for the abstract domain of polyhedra"

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.DM(Discrete Mathematics)