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: "automatic abstraction in smt based unbounded software model checking"
  Abstract: Software model checkers based on under-approximations and SMT solvers are very successful at verifying safety (i.e. reachability) properties. They combine two key ideas -- (a) "concreteness": a counterexample in an under-approximation is a counterexample in the original program as well, and (b) "generalization": a proof of safety of an under-approximation, produced by an SMT solver, are generalizable to proofs of safety of the original program. In this paper, we present a combination of "automatic abstraction" with the under-approximation-driven framework. We explore two iterative approaches for obtaining and refining abstractions -- "proof based" and "counterexample based" -- and show how they can be combined into a unified algorithm. To the best of our knowledge, this is the first application of Proof-Based Abstraction, primarily used to verify hardware, to Software Verification. We have implemented a prototype of the framework using Z3, and evaluate it on many benchmarks from the Software Verification Competition. We show experimentally that our combination is quite effective on hard instances.

Connected through hyperedge HE-1 (induced by source paper "consort context and flow sensitive ownership refinement types for imperative programs"):
  with members:
    - "dependent types for javascript"

Connected through hyperedge HE-2 (induced by source paper "solving horn clauses on inductive data types without induction"):
  with members:
    - "predicate pairing for program verification"
    - "automating induction for solving horn clauses"
    - "proving correctness of imperative programs by linearizing constrained horn clauses"
    - "verification of java bytecode using analysis and transformation of logic programs"
    - "the parma polyhedra library toward a complete set of numerical abstractions for the analysis and verification of hardware and software systems"

Connected through hyperedge HE-3 (induced by source paper "differentially testing soundness and precision of program analyzers"):
  with members:
    - "smt based model checking for recursive programs"
    - "formal verification of a c value analysis based on abstract interpretation"
    - "stratified static analysis based on variable dependencies"
    - "cpachecker a tool for configurable software verification"
    - "the octagon abstract domain"

Connected through hyperedge HE-4 (induced by source paper "combining forward and backward abstract interpretation of horn clauses"):
  with members:
    - "program analysis with local policy iteration"
    - "smt based model checking for recursive programs"
    - "pagai a path sensitive static analyzer"
    - "using bounded model checking to focus fixpoint iterations"
    - "the parma polyhedra library toward a complete set of numerical abstractions for the analysis and verification of hardware and software systems"

Connected through hyperedge HE-5 (induced by source paper "formula slicing inductive invariants from preconditions"):
  with members:
    - "program analysis with local policy iteration"
    - "pagai a path sensitive static analyzer"
    - "using bounded model checking to focus fixpoint iterations"
    - "software model checking via large block encoding"
    - "cpachecker a tool for configurable software verification"

Connected through hyperedge HE-6 (induced by source paper "hierarchical state machines as modular horn clauses"):
  with members:
    - "pkind a parallel k induction based model checker"

Connected through hyperedge HE-7 (induced by source paper "computing minimal sets on propositional formulae i problems reductions"):
  with members:
    - "discovering cyclic causal models with latent variables a general sat based procedure"
    - "cause clue clauses error localization using maximum satisfiability"
    - "redundancy in logic i cnf propositional formulae"
    - "redundancy in logic ii 2cnf and horn propositional formulae"
    - "propositional independence formula variable independence and forgetting"
    - "a knowledge compilation map"

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)