arXiv subjects

Andrey Rivkin

Publications and source records attributed to Andrey Rivkin.

22 records · Page 2Linked to original sources

arXiv2019

Quantifier Elimination for Database Driven Verification

Running verification tasks in database driven systems requires solving quantifier elimination problems of a new kind. These quantifier elimination problems are related to the notion of a cover introduced in ESOP 2008 by Gulwani and Musuvathi. In this paper, we show how covers are strictly related to model completions, a well-known topic in model theory. We also investigate the computation of covers within the Superposition Calculus, by adopting a constrained version of the calculus, equipped with appropriate settings and reduction strategies. In addition, we show that cover computations are computationally tractable for the fragment of the language used in applications to database driven verification. This observation is confirmed by analyzing the preliminary results obtained using the MCMT tool on the verification of data-aware process benchmarks. These benchmarks can be found in the last version of the tool distribution.

cs.LO↗

arXiv2019

From DB-nets to Coloured Petri Nets with Priorities (Extended Version)

The recently introduced formalism of DB-nets has brought in a new conceptual way of modelling complex dynamic systems that equally account for the process and data dimensions, considering local data as well as persistent, transactional data. DB-nets combine a coloured variant of Petri nets with name creation and management (which we call nu-CPN), with a relational database. The integration of these two components is realized by equipping the net with special ``view'' places that query the database and expose the resulting answers to the net, with actions that allow transitions to update the content of the database, and with special arcs capturing compensation in case of transaction failure. In this work, we study whether this sophisticated model can be encoded back into nu-CPNs. In particular, we show that the meaningful fragment of DB-nets where database queries are expressed using unions of conjunctive queries with inequalities can be faithfully encoded into $ν$-CPNs with transition priorities. This allows us to directly exploit state-of-the-art technologies such as CPN Tools to simulate and analyse this relevant class of DB-nets.

cs.LO↗

arXiv2019

Verification of Data-Aware Processes via Array-Based Systems (Extended Version)

We study verification over a general model of artifact-centric systems, to assess (parameterized) safety properties irrespectively of the initial database instance. We view such artifact systems as array-based systems, which allows us to check safety by adapting backward reachability, establishing for the first time a correspondence with model checking based on Satisfiability-Modulo-Theories (SMT). To do so, we make use of the model-theoretic machinery of model completion, which surprisingly turns out to be an effective tool for verification of relational systems, and represents the main original contribution of this paper. In this way, we pursue a twofold purpose. On the one hand, we reconstruct (restricted to safety) the essence of some important decidability results obtained in the literature for artifact-centric systems, and we devise a genuinely novel class of decidable cases. On the other, we are able to exploit SMT technology in implementations, building on the well-known MCMT model checker for array-based systems, and extending it to make all our foundational results fully operational.

cs.LO↗

arXiv2016

DB-Nets: on The Marriage of Colored Petri Nets and Relational Databases

The integrated management of business processes and mas- ter data is being increasingly considered as a fundamental problem, by both the academia and the industry. In this position paper, we focus on the foundations of the problem, arguing that contemporary approaches struggle to find a suitable equilibrium between data- and process-related aspects. We then propose db-nets, a new formal model that balances such two pillars through the marriage of colored Petri nets and relational databases. We invite the research community to build on this model, discussing its potential in modeling, formal verification, and simulation.

cs.DB↗