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 relational logic for higher order programs"
  Abstract: Relational program verification is a variant of program verification where one can reason about two programs and as a special case about two executions of a single program on different inputs. Relational program verification can be used for reasoning about a broad range of properties, including equivalence and refinement, and specialized notions such as continuity, information flow security or relative cost. In a higher-order setting, relational program verification can be achieved using relational refinement type systems, a form of refinement types where assertions have a relational interpretation. Relational refinement type systems excel at relating structurally equivalent terms but provide limited support for relating terms with very different structures. #R##N#We present a logic, called Relational Higher Order Logic (RHOL), for proving relational properties of a simply typed $\lambda$-calculus with inductive types and recursive definitions. RHOL retains the type-directed flavour of relational refinement type systems but achieves greater expressivity through rules which simultaneously reason about the two terms as well as rules which only contemplate one of the two terms. We show that RHOL has strong foundations, by proving an equivalence with higher-order logic (HOL), and leverage this equivalence to derive key meta-theoretical properties: subject reduction, admissibility of a transitivity rule and set-theoretical soundness. Moreover, we define sound embeddings for several existing relational type systems such as relational refinement types and type systems for dependency analysis and relative cost, and we verify examples that were out of reach of prior work.

Connected through hyperedge HE-1 (induced by source paper "operationally based program equivalence proofs using lctrss"):
  with members:
    - "a coinductive approach to proving reachability properties in logically constrained term rewriting systems"
    - "verifying procedural programs via constrained rewriting induction"

Connected through hyperedge HE-2 (induced by source paper "formal verification of higher order probabilistic programs reasoning about approximation convergence bayesian inference and optimization"):
  with members:
    - "equivalence between wasserstein and value aware model based reinforcement learning"
    - "relational reasoning for markov chains in a probabilistic guarded lambda calculus"
    - "measurable cones and stable measurable functions a model for probabilistic higher order programming"
    - "mixed powerdomains for probability and nondeterminism"
    - "a convenient category for higher order probability theory"
    - "denotational validation of higher order bayesian inference"
    - "a theory of slicing for probabilistic control flow graphs"
    - "a program logic for union bounds"

Connected through hyperedge HE-3 (induced by source paper "the next 700 relational program logics"):
  with members:
    - "synthetic topology in homotopy type theory for probabilistic programming"
    - "formal verification of higher order probabilistic programs reasoning about approximation convergence bayesian inference and optimization"
    - "journey beyond full abstraction exploring robust property preservation for secure compilation"
    - "proof relevant logical relations for name generation"
    - "relational cost analysis for functional imperative programs"
    - "coupling proofs are probabilistic product programs"
    - "relational reasoning via probabilistic coupling"
    - "abstract effects and proof relevant logical relations"

Connected through hyperedge HE-4 (induced by source paper "relational differential dynamic logic"):
  with members:
    - "differential equation axiomatization the impressive power of differential ghosts"
    - "probabilistic relational reasoning via metrics"
    - "ranking and repulsing supermartingales for reachability in probabilistic programs"
    - "the keymaera x proof ide concepts on usability in hybrid systems theorem proving"
    - "a complete uniform substitution calculus for differential dynamic logic"

Connected through hyperedge HE-5 (induced by source paper "responsibility analysis by abstract interpretation"):
  with members:
    - "cause clue clauses error localization using maximum satisfiability"
    - "provenance as dependency analysis"
    - "what causes a system to satisfy a specification"
    - "responsibility and blame a structural model approach"

Connected through hyperedge HE-6 (induced by source paper "relational reasoning for markov chains in a probabilistic guarded lambda calculus"):
  with members:
    - "proving uniformity and independence by self composition and coupling"
    - "the guarded lambda calculus programming and reasoning with guarded recursion for coinductive types"
    - "coupling proofs are probabilistic product programs"
    - "guarded dependent type theory with coinductive types"
    - "differentially private bayesian programming"
    - "relational reasoning via probabilistic coupling"
    - "a lambda calculus foundation for universal probabilistic programming"
    - "higher order approximate relational refinement types for mechanism design and differential privacy"

Connected through hyperedge HE-7 (induced by source paper "refinement types for ruby"):
  with members:
    - "verified low level programming embedded in f"
    - "refinement types for typescript"
    - "just in time static type checking for dynamic languages"
    - "jsketch sketching for java"
    - "occurrence typing modulo theories"
    - "automated feedback generation for introductory programming assignments"

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.PL(Programming Languages)