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: "fo fd extending classical logic with rule based fixpoint definitions"
  Abstract: We introduce fixpoint definitions, a rule-based reformulation of fixpoint constructs. The logic FO(FD), an extension of classical logic with fixpoint definitions, is defined. We illustrate the relation between FO(FD) and FO(ID), which is developed as an integration of two knowledge representation paradigms. The satisfiability problem for FO(FD) is investigated by first reducing FO(FD) to difference logic and then using solvers for difference logic. These reductions are evaluated in the computation of models for FO(FD) theories representing fairness conditions and we provide potential applications of FO(FD).

Connected through hyperedge HE-1 (induced by source paper "a restricted second order logic for non deterministic poly logarithmic time"):
  with members:
    - "the polylog time hierarchy captured by restricted second order logic"
    - "graph isomorphism in quasipolynomial time"
    - "predicate logic as a modeling language modeling and solving some machine learning and data mining problems with idp3"

Connected through hyperedge HE-2 (induced by source paper "knowledge of uncertain worlds programming with logical constraints"):
  with members:
    - "the founded semantics and constraint semantics of logic rules"
    - "semantics of templates in a compositional framework for building logics"

Connected through hyperedge HE-3 (induced by source paper "logic programming applications what are the abstractions and implementations"):
  with members:
    - "applp a dialogue on applications of logic programming"
    - "precise complexity guarantees for pointer analysis via datalog with extensions"
    - "the founded semantics and constraint semantics of logic rules"
    - "demand driven incremental object queries"
    - "team building with answer set programming in the gioia tauro seaport"
    - "xsb extending prolog with tabled logic programming"
    - "the dlv system for knowledge representation and reasoning"

Connected through hyperedge HE-4 (induced by source paper "constraint propagation for first order logic and inductive definitions"):
  with members:
    - "lifted unit propagation for effective grounding"
    - "grounding fo and fo id with bounds"
    - "design and implementation of aggregate functions in the dlv system"
    - "the dlv system for knowledge representation and reasoning"
    - "well founded and stable semantics of logic programs with aggregates"
    - "propositional satisfiability in answer set programming"
    - "extending classical logic with inductive definitions"
    - "smodels a system for answer set programming"

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)