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: "the abella interactive theorem prover system description"
  Abstract: Abella is an interactive system for reasoning about aspects of object languages that have been formally presented through recursive rules based on syntactic structure. Abella utilizes a two-level logic approach to specification and reasoning. One level is defined by a specification logic which supports a transparent encoding of structural semantics rules and also enables their execution. The second level, called the reasoning logic, embeds the specification logic and allows the development of proofs of properties about specifications. An important characteristic of both logics is that they exploit the lambda tree syntax approach to treating binding in object languages. Amongst other things, Abella has been used to prove normalizability properties of the lambda calculus, cut admissibility for a sequent calculus and type uniqueness and subject reduction properties. This paper discusses the logical foundations of Abella, outlines the style of theorem proving that it supports and finally describes some of its recent applications.

Connected through hyperedge HE-1 (induced by source paper "rapid prototyping formal systems in mmt 5 case studies"):
  with members:
    - "the mmt api a generic mkm system"
    - "theory presentation combinators"
    - "a query language for formal mathematical libraries"
    - "type classes for mathematics in type theory"
    - "a scalable module system"

Connected through hyperedge HE-2 (induced by source paper "formalization of metatheory of the quipper quantum programming language in a linear logic"):
  with members:
    - "qwire practice formal verification of quantum circuits in coq"
    - "enriching a linear non linear lambda calculus a programming language for string diagrams"
    - "an open challenge problem repository for systems supporting binders"
    - "reasoning about higher order relational specifications"
    - "quipper a scalable quantum programming language"
    - "an improved implementation and abstract interface for hybrid"
    - "a lambda calculus for quantum computation with classical control"
    - "reasoning with higher order abstract syntax in a logical framework"

Connected through hyperedge HE-3 (induced by source paper "on the expressive power of user defined effects effect handlers monadic reflection delimited control"):
  with members:
    - "factorisation systems for logical relations and monadic lifting in type and effect system semantics"
    - "no value restriction is needed for algebraic effects and handlers"
    - "do be do be do"
    - "answer type modification without tears prompt passing style translation for typed delimited control operators"
    - "programming with algebraic effects and handlers"
    - "inferring algebraic effects"
    - "an effect system for algebraic effects and handlers"
    - "combining and relating control effects and their semantics"

Connected through hyperedge HE-4 (induced by source paper "a higher order abstract syntax approach to the verified compilation of functional programs"):
  with members:
    - "a case study on logical relations using contextual types"
    - "the next 700 challenge problems for reasoning with higher order abstract syntax representations part 1 a common infrastructure for benchmarks"
    - "a framework for specifying prototyping and reasoning about computational systems"
    - "a two level logic approach to reasoning about computations"
    - "reasoning with higher order abstract syntax in a logical framework"

Connected through hyperedge HE-5 (induced by source paper "syntax and semantics of abstract binding trees"):
  with members:
    - "second order algebraic theories"

Connected through hyperedge HE-6 (induced by source paper "a case study on logical relations using contextual types"):
  with members:
    - "reasoning in abella about structural operational semantics specifications"
    - "combining generic judgments with recursive definitions"
    - "mechanizing the metatheory of lf"
    - "on equivalence and canonical forms in the lf type theory"

Connected through hyperedge HE-7 (induced by source paper "an open challenge problem repository for systems supporting binders"):
  with members:
    - "the next 700 challenge problems for reasoning with higher order abstract syntax representations part 1 a common infrastructure for benchmarks"
    - "reasoning about higher order relational specifications"
    - "a two level logic approach to reasoning about computations"

Connected through hyperedge HE-8 (induced by source paper "the next 700 challenge problems for reasoning with higher order abstract syntax representations part 1 a common infrastructure for benchmarks"):
  with members:
    - "towards extracting explicit proofs from totality checking in twelf"
    - "a two level logic approach to reasoning about computations"

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)