Towards a Formalisation of Graph Transformations in Proof Assistants

This paper takes first steps towards a formalization of graph transformations in a general setting of interactive theorem provers, which will form the basis for proofs of correctness of graph transformation systems. We present parts of our formalization and take a glimpse at some strategies for simplifying proof obligations

A case study in combining formal verification and model-driven engineering

International audienceFormal methods are increasingly used in software engineering. They offer a formal frame that guarentees the correctness of developments. However, they use complex notations that might be difficult to understand for unaccustomed users. It thus becomes interesting to formally specify the core components of a language, implement a provably correct development, and manipulate its components in a graphical/ textual editor. This paper constitutes a first step towards using Model Driven Engineering (MDE) technology in an interactive proof development. It presents a transformation process from functional data structures, commonly used in proof assistants, to Ecore Models. The transformation is based on an MDE methodology. The resulting meta-models are used to generate graphical or textual editors. We will take an example to illustrate our approach: a simple domain specific language. This guiding example is a Java-like language enriched with assertions

User Guided Abductive Proof Generation for Answer Set Programming Queries (Extended Version)

We present a method for generating possible proofs of a query with respect to a given Answer Set Programming (ASP) rule set using an abductive process where the space of abducibles is automatically constructed just from the input rules alone. Given a (possibly empty) set of user provided facts, our method infers any additional facts that may be needed for the entailment of a query and then outputs these extra facts, without the user needing to explicitly specify the space of all abducibles. We also present a method to generate a set of directed edges corresponding to the justification graph for the query. Furthermore, through different forms of implicit term substitution, our method can take user provided facts into account and suitably modify the abductive solutions. Past work on abduction has been primarily based on goal directed methods. However these methods can result in solvers that are not truly declarative. Much less work has been done on realizing abduction in a bottom up solver like the Clingo ASP solver. We describe novel ASP programs which can be run directly in Clingo to yield the abductive solutions and directed edge sets without needing to modify the underlying solving engine.Comment: 18 page

Verification of the Schorr-Waite Algorithm - From Trees to Graphs

16 pagesInternational audienceThis article proposes a method for proving the correctness of graph algorithms by manipulating their spanning trees enriched with additional references. We illustrate this concept with a proof of the correctness of a (pseudo-)imperative version of the Schorr-Waite algorithm by re finement of a functional one working on trees. It is composed of two orthogonal steps of re finement -- functional to imperative and tree to graph -- fi nally merged to obtain the result. Our imperative speci fications use monadic constructs and syntax sugar, making them close to common imperative languages. This work has been realized within the Isabelle/HOL proof assistant

Arte Rupestre de México Oriental y de Centro América

Este texto tiene carácter bibliográfico. Su propósito es ser una guía para la búsqueda de fuentes de información y ofrecer una introducción al estudio sistemático del arte rupestre en el oriente de México y en Centroamérica. Se dirige tanto a especialistas, estudiantes y aficionados, como a propietarios de arte rupestre o para los indígenas que asuman el rol de "custodios naturales" de sitios con representaciones rupestres. Se presenta el arte rupestre según la distribución política de los estados en el oriente de México y América Central. Los textos se basan en investigaciones propias de los autores e introducen al lector al estado actual de la investigación del arte rupestre en las regiones respectivas. Los autores presentan diferentes estrategias de investigación que dan una visión preliminar y diversa de las imágenes estudiadas.Centroamérica bara México Oriental ra blasi pyua wina wan almuka nani lilka satka nani paskanba. Naha ulbanka na taura wauhtaya wala kum wina wahbi sakan sa, diara kumra luki dauki bangwan ba sika naha nakku upla nani kaiki bangbia bara mahrikaia nahki Centroamerica bara Oriente de México ra blasi pyua wina lilka satka nani paski swinba stadika muni bangbia dukiara. Naha ulbanka na auya naha sat dukia kulka tadi muni uplika nanira, nahamuna sat dukia laik kaiki bangwi uplika nanira, nahamuna sat dukia dawan ka nanira, bara indian nani witing nani kan wina naha sat dukia nani ai tasbaia bilara brih main kaiki uplika nanira sin. Naha blasi wina paski swin dukia nani ba pliki saki bangwisa Centroamerica bara oriente de México ra witing nani nahki ai tasbaia baiki saki bri ba bilara. Naha wauhkataya nani na ulbansa upla kum yakan diara laki kaiki wahbi sakan dawanka bui bara ai kakaira nanira mahrikisa blasi pyua wina lilka satka nani paskan ba stadika ba nahki auya sa sapa naiwa yua kat tasba banira. Diara dawanka nani ba bui witing nanira mahrikisa satka ailal mapara naha lilkika nani kumi bani ba stadi munaia dukiara wiria wan marikisa

Polychronous Interpretation of Synoptic, a Domain Specific Modeling Language for Embedded Flight-Software

The SPaCIFY project, which aims at bringing advances in MDE to the satellite flight software industry, advocates a top-down approach built on a domain-specific modeling language named Synoptic. In line with previous approaches to real-time modeling such as Statecharts and Simulink, Synoptic features hierarchical decomposition of application and control modules in synchronous block diagrams and state machines. Its semantics is described in the polychronous model of computation, which is that of the synchronous language Signal.Comment: Workshop on Formal Methods for Aerospace (FMA 2009