Abstract The quest of smoothly combining logics so that connectives from different logics can co-exist in peace has been a fascinating topic of research. In 2015, Dag Prawitz introduced a natural deduction system for an ecumenical first-order logic, unifying classical and intuitionistic logics within a shared language. Building upon this foundation, we introduced, in a series of works, sequent systems for ecumenical logics and modal extensions. In this work we propose a new pure sequent calculus version for Prawitz’s original system, where each rule features precisely one logical operator. This is achieved by extending sequents with an additional context, called stoup, and establishing the ecumenical concept of polarities. We smoothly extend these ideas for handling modalities, presenting a new pure labelled system for ecumenical modal logics. Finally, we show how this allows for naturally retrieving the ecumenical modal nested system proposed in a previous work.

Abstract Data races are a particular kind of subtle, unintended program behaviour arising from thread interference in shared-memory concurrency. In this paper, we propose an automated technique for static detection of data races in multi-threaded C programs with POSIX threads. The key element of our technique is a reduction to reachability. Our prototype implementation combines such reduction with context-bounded analysis. The approach proves competitive against state-of-the-art tools, finding new issues in the implementation of well-known lock-free data structures, and shows a considerably superior accuracy of analysis in the presence of complex shared-memory access patterns.

Abstract We sketch a sequentialization-based technique for bounded detection of data races under sequential consistency, and summarise the major improvements to our verification framework over the last years.