human: Given a node-centered hypergraph: <hypergraph>, where nodes represent authors and hyperedges represent groups of authors who co-authored the same paper.

Details of the hypergraph:
Center node: "Lazy explanations for constraint propagators"
  Abstract: Explanations are a technique for reasoning about constraint propagation, which have been applied in many learning, backjumping and user-interaction algorithms for constraint programming. To date explanations for constraints have usually been recorded “eagerly” when constraint propagation happens, which leads to inefficient use of time and space, because many will never be used. In this paper we show that it is possible and highly effective to calculate explanations retrospectively when they are needed. To this end, we implement “lazy” explanations in a state of the art learning framework. Experimental results confirm the effectiveness of the technique: we achieve reduction in the number of explanations calculated up to a factor of 200 and reductions in overall solve time up to a factor of 5.

Connected through hyperedge HE-1 (induced by source paper "Learning When to Use Lazy Learning in Constraint Solving"):
  with members:
    (none)

Connected through hyperedge HE-2 (induced by source paper "Solving SAT and SAT Modulo Theories: From an abstract Davis--Putnam--Logemann--Loveland procedure to DPLL( T )"):
  with members:
    - "Potassco: The Potsdam Answer Set Solving Collection"
    - "Efficient conflict driven learning in a boolean satisfiability solver"
    - "Volume Computation for Boolean Combination of Linear Arithmetic Constraints"
    - "Abstract disjunctive answer set solvers"
    - "There are no CNF problems"
    - "Congruence closure of compressed terms in polynomial time"

Connected through hyperedge HE-3 (induced by source paper "Efficient conflict driven learning in a boolean satisfiability solver"):
  with members:
    - "Solving SAT and SAT Modulo Theories: From an abstract Davis--Putnam--Logemann--Loveland procedure to DPLL( T )"
    - "Analysis of Search Based Algorithms for Satisfiability of Quantified Boolean Formulas Arising from Circuit State Space Diameter Problems."
    - "A new approach to the maximum flow problem"
    - "Efficient Solving of Large Non-linear Arithmetic Constraint Systems with Complex Boolean Structure"

Question: Please tell me which research area the center author belongs to. The 4 classes are: Computer science, Mathematics, Engineering, Economics, Psychology, Business. Directly output the class name.

gpt: Computer science