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: "a maximal tractable class of soft constraints"
  Abstract: Many researchers in artificial intelligence are beginning to explore the use of soft constraints to express a set of (possibly conflicting) problem requirements. A soft constraint is a function defined on a collection of variables which associates some measure of desirability with each possible combination of values for those variables. However, the crucial question of the computational complexity of finding the optimal solution to a collection of soft constraints has so far received very little attention. In this paper we identify a class of soft binary constraints for which the problem of finding the optimal solution is tractable. In other words, we show that for any given set of such constraints, there exists a polynomial time algorithm to determine the assignment having the best overall combined measure of desirability. This tractable class includes many commonly-occurring soft constraints, such as 'as near as possible' or 'as soon as possible after', as well as crisp constraints such as 'greater than'. Finally, we show that this tractable class is maximal, in the sense that adding any other form of soft binary constraint which is not in the class gives rise to a class of problems which is NP-hard.

Connected through hyperedge HE-1 (induced by source paper "binarisation for valued constraint satisfaction problems"):
  with members:
    - "the power of sherali adams relaxations for general valued csps"
    - "a galois connection for weighted relational clones of infinite size"
    - "a finer reduction of constraint problems to digraphs"
    - "algebraic properties of valued constraint satisfaction problem"
    - "a reduction from valued csp to min cost homomorphism problem for digraphs"
    - "the complexity of general valued csps"
    - "sherali adams relaxations for valued csps"
    - "robustly solvable constraint satisfaction problems"

Connected through hyperedge HE-2 (induced by source paper "the complexity of approximating conservative counting csps"):
  with members:
    - "the complexity of conservative valued csps"
    - "the expressibility of functions on the boolean domain with applications to counting csps"
    - "the complexity of weighted and unweighted csp"
    - "approximating the partition function of the ferromagnetic potts model"
    - "complexity of counting csp with complex weights"
    - "approximate counting for complex weighted boolean constraint satisfaction problems"
    - "an effective dichotomy for the counting constraint satisfaction problem"
    - "non negative weighted csps an effective complexity dichotomy"

Connected through hyperedge HE-3 (induced by source paper "the expressive power of binary submodular functions"):
  with members:
    - "the approximability of max csp with fixed value constraints"
    - "the approximability of three valued max csp"

Connected through hyperedge HE-4 (induced by source paper "duality for min max orderings and dichotomy for min cost homomorphisms"):
  with members:
    - "minimum cost homomorphisms to reflexive digraphs"
    - "minimum cost and list homomorphisms to semicomplete digraphs"

Connected through hyperedge HE-5 (induced by source paper "minimum cost homomorphisms to locally semicomplete and quasi transitive digraphs"):
  with members:
    - "minimum cost homomorphisms to reflexive digraphs"
    - "minimum cost and list homomorphisms to semicomplete digraphs"
    - "minimum cost homomorphisms to semicomplete multipartite digraphs"

Connected through hyperedge HE-6 (induced by source paper "minimum cost homomorphisms to reflexive digraphs"):
  with members:
    - "on the complexity of the minimum cost homomorphism problem for reflexive multipartite tournaments"
    - "minimum cost and list homomorphisms to semicomplete digraphs"
    - "minimum cost homomorphisms to semicomplete multipartite digraphs"

Connected through hyperedge HE-7 (induced by source paper "minimum cost homomorphisms to proper interval graphs and bigraphs"):
  with members:
    - "minimum cost and list homomorphisms to semicomplete digraphs"
    - "minimum cost homomorphisms to semicomplete multipartite digraphs"

Connected through hyperedge HE-8 (induced by source paper "minimum cost homomorphisms to semicomplete multipartite digraphs"):
  with members:
    - "minimum cost homomorphisms to reflexive digraphs"
    - "minimum cost and list homomorphisms to semicomplete digraphs"

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.AI(Artificial Intelligence)